* Re: (subset) [PATCH v8 00/10] pmdomain: samsung: add support for Google GS101
From: Ulf Hansson @ 2026-03-31 9:01 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: Alim Akhtar, Rob Herring, Conor Dooley, Krzysztof Kozlowski,
Liam Girdwood, Mark Brown, André Draszik, Peter Griffin,
Tudor Ambarus, Juan Yescas, Will McVicker, kernel-team,
linux-arm-kernel, linux-samsung-soc, devicetree, linux-kernel,
linux-pm, Marek Szyprowski
In-Reply-To: <c4d6b758-474b-409d-b553-fa4ec1df494e@kernel.org>
On Mon, 30 Mar 2026 at 15:38, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On 30/03/2026 15:30, Ulf Hansson wrote:
> >
> > Usually we want bindings to go along with their respective drivers on
> > a subsystem basis.
> >
> > Both patch2 and patch4 updates DT bindings for the power-domain providers.
>
> Patch 2 yes. Patch 4 not. That's why I did not take patch 2.
>
> >
> > Why shouldn't the bindings go along with the driver changes here?
>
> Patch #2 is pmdomain, so with pmdomain drivers thus your tree. Patch #4
> is not pmdomain, so not with pmdomain drivers, so not your tree... At
> least I do not see any pmdomain parts in that patch #4. It's a Samsung
> SoC PMU driver and none of further driver patches touch that PMU driver.
Yes, you are right that the PMU driver isn't touched.
Although, the PMU DT description added in patch3 and extended in
patch4, allows power-domain providers to be described in its child
nodes. Those child nodes use the same compatible string as the
power-domain providers described in patch2.
Kind regards
Uffe
^ permalink raw reply
* Re: [PATCH v4 2/3] driver core: make software nodes available earlier
From: Bartosz Golaszewski @ 2026-03-31 8:58 UTC (permalink / raw)
To: Andy Shevchenko
Cc: Dmitry Torokhov, Bartosz Golaszewski, Greg Kroah-Hartman,
Rafael J. Wysocki, Danilo Krummrich, Daniel Scally,
Heikki Krogerus, Sakari Ailus, Aaro Koskinen, Janusz Krzysztofik,
Tony Lindgren, Russell King, Kevin Hilman, Arnd Bergmann,
driver-core, linux-kernel, linux-acpi, linux-arm-kernel,
linux-omap
In-Reply-To: <acuMD7Oly4XWW4n8@ashevche-desk.local>
On Tue, Mar 31, 2026 at 10:55 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Mon, Mar 30, 2026 at 11:52:34PM -0700, Dmitry Torokhov wrote:
> > On March 30, 2026 11:25:33 PM PDT, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> > >On Mon, Mar 30, 2026 at 02:46:45PM -0700, Dmitry Torokhov wrote:
> > >> On Mon, Mar 30, 2026 at 11:24:45PM +0300, Andy Shevchenko wrote:
> > >> > On Mon, Mar 30, 2026 at 02:40:47PM +0200, Bartosz Golaszewski wrote:
>
> ...
>
> > >> > > -static void __exit software_node_exit(void)
> > >> > > -{
> > >> > > - ida_destroy(&swnode_root_ids);
> > >> > > - kset_unregister(swnode_kset);
> > >> > > }
> > >> > > -__exitcall(software_node_exit);
> > >> >
> > >> > Why? What's wrong with the __exitcall?
> > >>
> > >> It's dead code. Always was, always will be.
> > >>
> > >> Maybe split in a separate patch, but I sometimes feel the idea of "one
> > >> change" is taken to extreme and adds to both developer's and maintainers
> > >> burden by needing to keep track of extra patches.
> > >
> > >Why does __exitcall() exist then? It's also used in other places.
> > >I think it's generally good to have a possibility to clean up
> > >after run.
> >
> > The code section will be discarded when the kernel finishes booting so it
> > only increases image size on disk.
>
> Almost true. Interesting microblaze case, where it's not discarded.
> But I can't find where it's actually used on any architecture.
>
> > >A bit of archaeology:
> > >
> > >The first time it appeared was in the bcc2152647b8 ("Import 2.4.0-test3pre3").
> > >Then somehow spread a bit (but not much).
> >
> > And it shows how useful it is. Maybe it had some purpose a long time ago, but
> > at present time this code will never be executed since it cannot be built as
> > a module.
>
> Are you sure about definition of __exitcall? As I read init.h the macro
> is defined when it's not a MODULE.
>
> Anyways, if we going to drop that, it should be in a separate change
> explaining all these.
>
Sure. We must drop it too because the initialization no longer happens
in an initcall but is called from elsewhere so - were it not dead code
- we could end up with it being called before the init function.
Bart
^ permalink raw reply
* Re: [PATCH 1/1] net: ipv6: flowlabel: defer exclusive option free until RCU teardown
From: Eric Dumazet @ 2026-03-31 8:56 UTC (permalink / raw)
To: Ren Wei
Cc: security, davem, dsahern, kuba, pabeni, horms, afaerber, mani,
yoshfuji, yifanwucs, tomapufckgml, yuantan098, bird, enjou1224z,
zcliangcn, netdev, linux-arm-kernel, linux-actions, linux-kernel
In-Reply-To: <07351f0ec47bcee289576f39f9354f4a64add6e4.1774855883.git.zcliangcn@gmail.com>
On Mon, Mar 30, 2026 at 1:52 AM Ren Wei <n05ec@lzu.edu.cn> wrote:
>
> From: Zhengchuan Liang <zcliangcn@gmail.com>
>
> `ip6fl_seq_show()` walks the global flowlabel hash under the seq-file
> RCU read-side lock and prints `fl->opt->opt_nflen` when an option block
> is present.
>
> Exclusive flowlabels currently free `fl->opt` as soon as `fl->users`
> drops to zero in `fl_release()`. However, the surrounding
> `struct ip6_flowlabel` remains visible in the global hash table until
> later garbage collection removes it and `fl_free_rcu()` finally tears it
> down.
>
> A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that
> early `kfree()` and dereference freed option state, triggering a crash
> in `ip6fl_seq_show()`.
>
> Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches
> the lifetime already required for the enclosing flowlabel while readers
> can still reach it under RCU.
>
> Fixes: d3aedd5ebd4b ("ipv6 flowlabel: Convert hash list to RCU.")
> Reported-by: Yifan Wu <yifanwucs@gmail.com>
> Reported-by: Juefei Pu <tomapufckgml@gmail.com>
> Co-developed-by: Yuan Tan <yuantan098@gmail.com>
> Signed-off-by: Yuan Tan <yuantan098@gmail.com>
> Suggested-by: Xin Liu <bird@lzu.edu.cn>
> Tested-by: Ren Wei <enjou1224z@gmail.com>
> Signed-off-by: Zhengchuan Liang <zcliangcn@gmail.com>
> Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Quite a long and confusing list of tags, and a long CC list ...
Please trim this next time you submit a networking patch.
Reviewed-by: Eric Dumazet <edumazet@google.com>
^ permalink raw reply
* Re: [PATCH v4 2/3] driver core: make software nodes available earlier
From: Andy Shevchenko @ 2026-03-31 8:55 UTC (permalink / raw)
To: Dmitry Torokhov
Cc: Bartosz Golaszewski, Greg Kroah-Hartman, Rafael J. Wysocki,
Danilo Krummrich, Daniel Scally, Heikki Krogerus, Sakari Ailus,
Aaro Koskinen, Janusz Krzysztofik, Tony Lindgren, Russell King,
Kevin Hilman, Arnd Bergmann, brgl, driver-core, linux-kernel,
linux-acpi, linux-arm-kernel, linux-omap
In-Reply-To: <DDF494E5-C188-4A86-AC02-265B6169B591@gmail.com>
On Mon, Mar 30, 2026 at 11:52:34PM -0700, Dmitry Torokhov wrote:
> On March 30, 2026 11:25:33 PM PDT, Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> >On Mon, Mar 30, 2026 at 02:46:45PM -0700, Dmitry Torokhov wrote:
> >> On Mon, Mar 30, 2026 at 11:24:45PM +0300, Andy Shevchenko wrote:
> >> > On Mon, Mar 30, 2026 at 02:40:47PM +0200, Bartosz Golaszewski wrote:
...
> >> > > -static void __exit software_node_exit(void)
> >> > > -{
> >> > > - ida_destroy(&swnode_root_ids);
> >> > > - kset_unregister(swnode_kset);
> >> > > }
> >> > > -__exitcall(software_node_exit);
> >> >
> >> > Why? What's wrong with the __exitcall?
> >>
> >> It's dead code. Always was, always will be.
> >>
> >> Maybe split in a separate patch, but I sometimes feel the idea of "one
> >> change" is taken to extreme and adds to both developer's and maintainers
> >> burden by needing to keep track of extra patches.
> >
> >Why does __exitcall() exist then? It's also used in other places.
> >I think it's generally good to have a possibility to clean up
> >after run.
>
> The code section will be discarded when the kernel finishes booting so it
> only increases image size on disk.
Almost true. Interesting microblaze case, where it's not discarded.
But I can't find where it's actually used on any architecture.
> >A bit of archaeology:
> >
> >The first time it appeared was in the bcc2152647b8 ("Import 2.4.0-test3pre3").
> >Then somehow spread a bit (but not much).
>
> And it shows how useful it is. Maybe it had some purpose a long time ago, but
> at present time this code will never be executed since it cannot be built as
> a module.
Are you sure about definition of __exitcall? As I read init.h the macro
is defined when it's not a MODULE.
Anyways, if we going to drop that, it should be in a separate change
explaining all these.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply
* [PATCH v3] PCI: imx6: Don't remove MSI capability for i.MX7D/i.MX8M
From: Richard Zhu @ 2026-03-31 8:52 UTC (permalink / raw)
To: frank.li, l.stach, lpieralisi, kwilczynski, mani, robh, bhelgaas,
s.hauer, kernel, festevam
Cc: linux-pci, linux-arm-kernel, imx, linux-kernel, Richard Zhu,
stable
The MSI trigger mechanism for endpoint devices connected to i.MX7D,
i.MX8MM, and i.MX8MQ PCIe root complex ports depends on the MSI
capability register settings in the root complex. Removing the MSI
capability breaks MSI functionality for these endpoints.
Add keep_rp_msi_en flag to indicate platforms (i.MX7D, i.MX8MM, i.MX8MQ)
that should preserve the MSI capability during initialization.
Cc: stable@vger.kernel.org
Fixes: f5cd8a929c825 ("PCI: dwc: Remove MSI/MSIX capability for Root Port if iMSI-RX is used as MSI controller")
Suggested-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
---
v3 changes:
Use a flag 'dw_pcie_rp::keep_rp_msi_en' to identify SoCs that require MSI
capability preservation, and skip the capability removal in
pcie-designware-host.c accordingly.
v2 changes:
CC stable tree.
---
drivers/pci/controller/dwc/pci-imx6.c | 7 +++++++
drivers/pci/controller/dwc/pcie-designware-host.c | 2 +-
drivers/pci/controller/dwc/pcie-designware.h | 1 +
3 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 20dafd2710a3..fde173770933 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -117,6 +117,8 @@ enum imx_pcie_variants {
#define IMX_PCIE_FLAG_HAS_LUT BIT(10)
#define IMX_PCIE_FLAG_8GT_ECN_ERR051586 BIT(11)
#define IMX_PCIE_FLAG_SKIP_L23_READY BIT(12)
+/* Preserve MSI capability for platforms that require it */
+#define IMX_PCIE_FLAG_KEEP_MSI_CAP BIT(13)
#define imx_check_flag(pci, val) (pci->drvdata->flags & val)
@@ -1820,6 +1822,8 @@ static int imx_pcie_probe(struct platform_device *pdev)
} else {
if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_SKIP_L23_READY))
pci->pp.skip_l23_ready = true;
+ if (imx_check_flag(imx_pcie, IMX_PCIE_FLAG_KEEP_MSI_CAP))
+ pci->pp.keep_rp_msi_en = true;
pci->pp.use_atu_msg = true;
ret = dw_pcie_host_init(&pci->pp);
if (ret < 0)
@@ -1897,6 +1901,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
[IMX7D] = {
.variant = IMX7D,
.flags = IMX_PCIE_FLAG_SUPPORTS_SUSPEND |
+ IMX_PCIE_FLAG_KEEP_MSI_CAP |
IMX_PCIE_FLAG_HAS_APP_RESET |
IMX_PCIE_FLAG_SKIP_L23_READY |
IMX_PCIE_FLAG_HAS_PHY_RESET,
@@ -1909,6 +1914,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
[IMX8MQ] = {
.variant = IMX8MQ,
.flags = IMX_PCIE_FLAG_HAS_APP_RESET |
+ IMX_PCIE_FLAG_KEEP_MSI_CAP |
IMX_PCIE_FLAG_HAS_PHY_RESET |
IMX_PCIE_FLAG_SUPPORTS_SUSPEND,
.gpr = "fsl,imx8mq-iomuxc-gpr",
@@ -1923,6 +1929,7 @@ static const struct imx_pcie_drvdata drvdata[] = {
[IMX8MM] = {
.variant = IMX8MM,
.flags = IMX_PCIE_FLAG_SUPPORTS_SUSPEND |
+ IMX_PCIE_FLAG_KEEP_MSI_CAP |
IMX_PCIE_FLAG_HAS_PHYDRV |
IMX_PCIE_FLAG_HAS_APP_RESET,
.gpr = "fsl,imx8mm-iomuxc-gpr",
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index a74339982c24..7b5558561e15 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -1171,7 +1171,7 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
* the MSI and MSI-X capabilities of the Root Port to allow the drivers
* to fall back to INTx instead.
*/
- if (pp->use_imsi_rx) {
+ if (pp->use_imsi_rx && !pp->keep_rp_msi_en) {
dw_pcie_remove_capability(pci, PCI_CAP_ID_MSI);
dw_pcie_remove_capability(pci, PCI_CAP_ID_MSIX);
}
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index ae6389dd9caa..b12c5334552c 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -421,6 +421,7 @@ struct dw_pcie_host_ops {
struct dw_pcie_rp {
bool use_imsi_rx:1;
+ bool keep_rp_msi_en:1;
bool cfg0_io_shared:1;
u64 cfg0_base;
void __iomem *va_cfg0_base;
--
2.37.1
^ permalink raw reply related
* Re: [GIT PULL 6/7] arm64: tegra: Device tree changes for v7.1-rc1
From: Thierry Reding @ 2026-03-31 8:43 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: arm, soc, Thierry Reding, Jon Hunter, linux-tegra,
linux-arm-kernel
In-Reply-To: <e5327cd9-4aa1-4e26-b748-dd1af29e6fdb@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 3992 bytes --]
On Tue, Mar 31, 2026 at 10:00:01AM +0200, Krzysztof Kozlowski wrote:
> On 31/03/2026 09:53, Thierry Reding wrote:
> > On Mon, Mar 30, 2026 at 01:45:24PM +0200, Krzysztof Kozlowski wrote:
> >> On 29/03/2026 17:10, Thierry Reding wrote:
> >>> From: Thierry Reding <thierry.reding@gmail.com>
> >>>
> >>> Hi ARM SoC maintainers,
> >>>
> >>> The following changes since commit 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f:
> >>>
> >>> Linux 7.0-rc1 (2026-02-22 13:18:59 -0800)
> >>>
> >>> are available in the Git repository at:
> >>>
> >>> git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux.git tags/tegra-for-7.1-arm64-dt
> >>>
> >>> for you to fetch changes up to c70e6bc11d2008fbb19695394b69fd941ab39030:
> >>>
> >>> arm64: tegra: Add Tegra264 GPIO controllers (2026-03-28 01:36:46 +0100)
> >>>
> >>> Thanks,
> >>> Thierry
> >>>
> >>> ----------------------------------------------------------------
> >>> arm64: tegra: Device tree changes for v7.1-rc1
> >>>
> >>> Various fixes and new additions across a number of devices. GPIO and PCI
> >>> are enabled on Tegra264 and the Jetson AGX Thor Developer Kit, allowing
> >>> it to boot via network and mass storage.
> >>>
> >>> ----------------------------------------------------------------
> >>> Diogo Ivo (1):
> >>> arm64: tegra: smaug: Enable SPI-NOR flash
> >>>
> >>> Jon Hunter (1):
> >>> arm64: tegra: Fix RTC aliases
> >>>
> >>> Prathamesh Shete (1):
> >>> arm64: tegra: Add Tegra264 GPIO controllers
> >>>
> >>> Thierry Reding (6):
> >>> dt-bindings: pci: Document the NVIDIA Tegra264 PCIe controller
> >>
> >>
> >> This is unreviewed/unacked binding where PCI maintainers had 1 day to
> >> react to your v3.
> >
> > Rob gave a reviewed-by on this about a week ago:
> >
> > https://lore.kernel.org/linux-tegra/177440189257.2451552.18196101830235626115.robh@kernel.org/
>
> Rob, although knows a lot about PCI, is not a formally a PCI subsystem
> maintainer.
>
> >
> > In my experience the PCI maintainers typically defer review of the DT
> > bindings to DT maintainers, so I considered Rob's R-b sufficient.
>
> Sure and they acknowledge this, that review is done and patch can go
> other way, with "Ack".
No they don't. The vast majority of the PCI DT bindings patches are
indeed applied by the PCI maintainers, but for those that aren't (there
are, admittedly, only a handful over the last few years) there were no
Acked-bys from the PCI maintainers.
> Where is the Ack?
Again, this is where your rules start to fail to meet demands. As it is,
the only option that we have is to get DT and drivers merged, then wait
for an entire cycle before we can merge the DT parts, otherwise we break
DT validation.
> >
> >> Maybe they had more time for previous versions, but
> >> nevertheless it is also part of other patchset, so it will get into the
> >> kernel other tree and nothing on v3 posting:
> >> https://lore.kernel.org/all/20260326135855.2795149-4-thierry.reding@kernel.org/
> >> gives hints that there will be cross tree merge.
> >
> > Maybe look at the cover letter:
> >
> > https://lore.kernel.org/all/20260326135855.2795149-1-thierry.reding@kernel.org/
> >
> > I clearly pointed out the build dependencies and suggested a shared
> > branch to resolve them in both trees. Given that the bindings were
>
> No problem, that's a valid solution. Can you point me with a lore link
> to the shared branch posting (these tags/pull requests must be posted on
> the lists)? Or to an ack from PCI maintainers?
>
> The commit itself does not have an Ack, but maybe was just missed.
Yes, the DT bindings patch does not have an Acked-by, but again, I
didn't think that was necessary, especially since we were going to have
a cross-merge anyway.
Here's the PR for PCI:
https://lore.kernel.org/linux-tegra/20260329155040.1448158-1-thierry.reding@kernel.org/
Thierry
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^ permalink raw reply
* [linux-next:master] [randomize_kstack] a96ef5848c: will-it-scale.per_thread_ops 7.7% improvement
From: kernel test robot @ 2026-03-31 8:41 UTC (permalink / raw)
To: Ryan Roberts
Cc: oe-lkp, lkp, Kees Cook, Mark Rutland, linux-kernel,
linux-arm-kernel, loongarch, linuxppc-dev, linux-riscv,
linux-s390, linux-hardening, oliver.sang
Hello,
kernel test robot noticed a 7.7% improvement of will-it-scale.per_thread_ops on:
commit: a96ef5848cb096226bf6aff31a90d8b136d99b71 ("randomize_kstack: Unify random source across arches")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
testcase: will-it-scale
config: x86_64-rhel-9.4
compiler: gcc-14
test machine: 192 threads 2 sockets Intel(R) Xeon(R) 6740E CPU @ 2.4GHz (Sierra Forest) with 256G memory
parameters:
nr_task: 100%
mode: thread
test: lseek1
cpufreq_governor: performance
In addition to that, the commit also has significant impact on the following tests:
+------------------+--------------------------------------------------------------+
| testcase: change | will-it-scale: will-it-scale.per_thread_ops 4.7% improvement |
| test parameters | cpufreq_governor=performance |
| | mode=thread |
| | nr_task=100% |
| | test=getppid1 |
+------------------+--------------------------------------------------------------+
Details are as below:
-------------------------------------------------------------------------------------------------->
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260331/202603311659.6aa92f2c-lkp@intel.com
=========================================================================================
compiler/cpufreq_governor/kconfig/mode/nr_task/rootfs/tbox_group/test/testcase:
gcc-14/performance/x86_64-rhel-9.4/thread/100%/debian-13-x86_64-20250902.cgz/lkp-srf-2sp2/lseek1/will-it-scale
commit:
37beb42560 ("randomize_kstack: Maintain kstack_offset per task")
a96ef5848c ("randomize_kstack: Unify random source across arches")
37beb42560165869 a96ef5848cb096226bf6aff31a9
---------------- ---------------------------
%stddev %change %stddev
\ | \
1.474e+09 +7.7% 1.588e+09 will-it-scale.192.threads
7675604 +7.7% 8270154 will-it-scale.per_thread_ops
1.474e+09 +7.7% 1.588e+09 will-it-scale.workload
37.77 -16.4% 31.57 vmstat.cpu.us
60.95 +6.2 67.17 mpstat.cpu.all.sys%
38.17 -6.3 31.90 mpstat.cpu.all.usr%
0.96 +17.7% 1.13 turbostat.IPC
442.92 +3.6% 459.07 turbostat.PkgWatt
0.01 ± 22% -28.9% 0.01 ± 20% perf-stat.i.MPKI
1.295e+11 +11.4% 1.442e+11 perf-stat.i.branch-instructions
7450278 ± 77% +144.3% 18200516 ± 35% perf-stat.i.branch-misses
4646936 ± 5% -10.0% 4180940 ± 5% perf-stat.i.cache-references
1.04 -15.2% 0.88 perf-stat.i.cpi
5.856e+11 +18.0% 6.907e+11 perf-stat.i.instructions
0.96 +18.0% 1.13 perf-stat.i.ipc
0.00 ± 3% -15.2% 0.00 ± 2% perf-stat.overall.MPKI
0.01 ± 77% +0.0 0.01 ± 35% perf-stat.overall.branch-miss-rate%
10.98 ± 5% +1.3 12.24 ± 5% perf-stat.overall.cache-miss-rate%
1.04 -15.3% 0.88 perf-stat.overall.cpi
0.96 +18.0% 1.13 perf-stat.overall.ipc
119899 +9.5% 131347 perf-stat.overall.path-length
1.29e+11 +11.4% 1.437e+11 perf-stat.ps.branch-instructions
7425104 ± 77% +144.1% 18126281 ± 35% perf-stat.ps.branch-misses
4734855 ± 5% -10.3% 4248990 ± 5% perf-stat.ps.cache-references
5.837e+11 +18.0% 6.885e+11 perf-stat.ps.instructions
1.767e+14 +18.0% 2.086e+14 perf-stat.total.instructions
8.77 ± 2% -8.8 0.00 perf-profile.calltrace.cycles-pp.arch_exit_to_user_mode_prepare.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
39.72 -8.2 31.51 ± 5% perf-profile.calltrace.cycles-pp.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
42.72 -8.0 34.73 ± 5% perf-profile.calltrace.cycles-pp.entry_SYSCALL_64_after_hwframe.llseek
26.12 -2.5 23.64 ± 4% perf-profile.calltrace.cycles-pp.__x64_sys_lseek.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
13.12 ± 3% -1.7 11.38 ± 6% perf-profile.calltrace.cycles-pp.fdget_pos.__x64_sys_lseek.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
7.17 ± 3% -1.4 5.74 ± 7% perf-profile.calltrace.cycles-pp.__fget_files.fdget_pos.__x64_sys_lseek.do_syscall_64.entry_SYSCALL_64_after_hwframe
4.86 -0.3 4.53 ± 4% perf-profile.calltrace.cycles-pp.mutex_unlock.__x64_sys_lseek.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
1.39 +0.3 1.68 ± 7% perf-profile.calltrace.cycles-pp.lseek@plt
2.48 ± 2% +0.5 3.02 ± 8% perf-profile.calltrace.cycles-pp.testcase
1.20 ± 5% +1.2 2.39 ± 8% perf-profile.calltrace.cycles-pp.x64_sys_call.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
0.00 +1.4 1.40 ± 8% perf-profile.calltrace.cycles-pp.prandom_u32_state.do_syscall_64.entry_SYSCALL_64_after_hwframe.llseek
39.88 +7.5 47.39 ± 4% perf-profile.calltrace.cycles-pp.entry_SYSCALL_64.llseek
8.77 ± 2% -8.5 0.29 ± 5% perf-profile.children.cycles-pp.arch_exit_to_user_mode_prepare
39.86 -8.2 31.69 ± 5% perf-profile.children.cycles-pp.do_syscall_64
42.77 -8.0 34.78 ± 5% perf-profile.children.cycles-pp.entry_SYSCALL_64_after_hwframe
26.26 -2.4 23.83 ± 4% perf-profile.children.cycles-pp.__x64_sys_lseek
13.22 ± 3% -1.8 11.44 ± 6% perf-profile.children.cycles-pp.fdget_pos
7.24 ± 3% -1.4 5.79 ± 7% perf-profile.children.cycles-pp.__fget_files
98.29 -0.4 97.92 perf-profile.children.cycles-pp.llseek
4.92 -0.3 4.59 ± 4% perf-profile.children.cycles-pp.mutex_unlock
0.20 ± 2% -0.0 0.18 ± 2% perf-profile.children.cycles-pp.asm_sysvec_apic_timer_interrupt
0.19 -0.0 0.16 ± 2% perf-profile.children.cycles-pp.sysvec_apic_timer_interrupt
0.18 -0.0 0.15 ± 3% perf-profile.children.cycles-pp.hrtimer_interrupt
0.18 ± 2% -0.0 0.16 ± 2% perf-profile.children.cycles-pp.__sysvec_apic_timer_interrupt
0.10 ± 3% -0.0 0.08 ± 4% perf-profile.children.cycles-pp.__hrtimer_run_queues
0.10 -0.0 0.08 ± 4% perf-profile.children.cycles-pp.tick_nohz_handler
0.08 -0.0 0.06 ± 7% perf-profile.children.cycles-pp.update_process_times
0.76 ± 2% +0.2 0.92 ± 7% perf-profile.children.cycles-pp.lseek@plt
2.43 ± 2% +0.5 2.95 ± 8% perf-profile.children.cycles-pp.testcase
1.22 ± 4% +1.2 2.45 ± 8% perf-profile.children.cycles-pp.x64_sys_call
0.00 +1.4 1.40 ± 8% perf-profile.children.cycles-pp.prandom_u32_state
26.94 +4.7 31.60 ± 4% perf-profile.children.cycles-pp.entry_SYSCALL_64
8.72 ± 2% -8.5 0.23 ± 5% perf-profile.self.cycles-pp.arch_exit_to_user_mode_prepare
7.18 ± 3% -1.4 5.78 ± 7% perf-profile.self.cycles-pp.__fget_files
4.84 -0.3 4.52 ± 4% perf-profile.self.cycles-pp.mutex_unlock
1.07 ± 3% -0.1 0.94 ± 7% perf-profile.self.cycles-pp.fdget_pos
0.06 ± 7% +0.0 0.08 ± 10% perf-profile.self.cycles-pp.lseek@plt
3.62 +0.2 3.83 ± 4% perf-profile.self.cycles-pp.do_syscall_64
1.68 ± 2% +0.4 2.05 ± 8% perf-profile.self.cycles-pp.testcase
1.16 ± 5% +1.3 2.41 ± 8% perf-profile.self.cycles-pp.x64_sys_call
0.00 +1.3 1.33 ± 8% perf-profile.self.cycles-pp.prandom_u32_state
13.18 ± 2% +1.7 14.89 ± 6% perf-profile.self.cycles-pp.entry_SYSCALL_64
18.28 +3.9 22.16 ± 5% perf-profile.self.cycles-pp.llseek
***************************************************************************************************
=========================================================================================
compiler/cpufreq_governor/kconfig/mode/nr_task/rootfs/tbox_group/test/testcase:
gcc-14/performance/x86_64-rhel-9.4/thread/100%/debian-13-x86_64-20250902.cgz/lkp-srf-2sp2/getppid1/will-it-scale
commit:
37beb42560 ("randomize_kstack: Maintain kstack_offset per task")
a96ef5848c ("randomize_kstack: Unify random source across arches")
37beb42560165869 a96ef5848cb096226bf6aff31a9
---------------- ---------------------------
%stddev %change %stddev
\ | \
1.987e+09 +4.7% 2.079e+09 will-it-scale.192.threads
10346487 +4.7% 10828131 will-it-scale.per_thread_ops
1.987e+09 +4.7% 2.079e+09 will-it-scale.workload
0.79 +20.3% 0.95 turbostat.IPC
53.28 +3.8 57.11 mpstat.cpu.all.sys%
45.85 -3.8 42.01 mpstat.cpu.all.usr%
1.111e+11 +10.2% 1.225e+11 perf-stat.i.branch-instructions
4803948 ± 2% +9.6% 5267473 ± 5% perf-stat.i.cache-references
1.27 -17.3% 1.05 perf-stat.i.cpi
4.821e+11 +21.0% 5.833e+11 perf-stat.i.instructions
0.79 +20.9% 0.95 perf-stat.i.ipc
0.00 ± 4% -18.4% 0.00 ± 3% perf-stat.overall.MPKI
0.01 ± 60% -0.0 0.00 perf-stat.overall.branch-miss-rate%
1.27 -17.3% 1.05 perf-stat.overall.cpi
0.79 +21.0% 0.95 perf-stat.overall.ipc
73248 +15.6% 84666 perf-stat.overall.path-length
1.107e+11 +10.2% 1.221e+11 perf-stat.ps.branch-instructions
4903095 ± 2% +9.2% 5356604 ± 4% perf-stat.ps.cache-references
4.806e+11 +21.0% 5.814e+11 perf-stat.ps.instructions
1.455e+14 +21.0% 1.76e+14 perf-stat.total.instructions
4.78 ± 16% -2.7 2.06 ± 5% perf-profile.calltrace.cycles-pp.syscall_return_via_sysret.getppid
5.09 ± 9% -2.5 2.58 ± 10% perf-profile.calltrace.cycles-pp.__task_pid_nr_ns.__x64_sys_getppid.do_syscall_64.entry_SYSCALL_64_after_hwframe.getppid
5.69 ± 8% -2.5 3.18 ± 10% perf-profile.calltrace.cycles-pp.__x64_sys_getppid.do_syscall_64.entry_SYSCALL_64_after_hwframe.getppid
6.88 ± 3% -2.2 4.72 ± 16% perf-profile.calltrace.cycles-pp.entry_SYSCALL_64_safe_stack.getppid
1.36 ± 2% +1.0 2.38 ± 13% perf-profile.calltrace.cycles-pp.x64_sys_call.do_syscall_64.entry_SYSCALL_64_after_hwframe.getppid
0.00 +1.5 1.50 ± 15% perf-profile.calltrace.cycles-pp.getppid@plt
0.00 +1.9 1.88 ± 14% perf-profile.calltrace.cycles-pp.prandom_u32_state.do_syscall_64.entry_SYSCALL_64_after_hwframe.getppid
5.46 ± 17% +2.1 7.56 ± 5% perf-profile.calltrace.cycles-pp.entry_SYSRETQ_unsafe_stack.getppid
10.78 ± 5% +3.8 14.62 ± 10% perf-profile.calltrace.cycles-pp.testcase
44.13 ± 7% -5.9 38.20 ± 5% perf-profile.children.cycles-pp.entry_SYSCALL_64
4.84 ± 16% -2.7 2.16 ± 6% perf-profile.children.cycles-pp.syscall_return_via_sysret
5.85 ± 9% -2.6 3.28 ± 11% perf-profile.children.cycles-pp.__x64_sys_getppid
5.17 ± 9% -2.5 2.64 ± 11% perf-profile.children.cycles-pp.__task_pid_nr_ns
6.04 ± 3% -1.8 4.22 ± 15% perf-profile.children.cycles-pp.entry_SYSCALL_64_safe_stack
2.12 ± 10% -1.7 0.38 ± 12% perf-profile.children.cycles-pp.arch_exit_to_user_mode_prepare
98.57 -0.6 97.99 perf-profile.children.cycles-pp.getppid
0.51 ± 7% +0.3 0.83 ± 14% perf-profile.children.cycles-pp.getppid@plt
1.44 ± 2% +1.0 2.42 ± 13% perf-profile.children.cycles-pp.x64_sys_call
0.00 +1.9 1.88 ± 14% perf-profile.children.cycles-pp.prandom_u32_state
6.32 ± 5% +2.4 8.68 ± 11% perf-profile.children.cycles-pp.testcase
20.95 ± 9% +10.1 31.04 ± 9% perf-profile.children.cycles-pp.entry_SYSRETQ_unsafe_stack
23.16 ± 6% -7.0 16.11 ± 16% perf-profile.self.cycles-pp.entry_SYSCALL_64
4.79 ± 16% -2.6 2.16 ± 6% perf-profile.self.cycles-pp.syscall_return_via_sysret
5.09 ± 9% -2.5 2.60 ± 11% perf-profile.self.cycles-pp.__task_pid_nr_ns
2.04 ± 10% -1.7 0.33 ± 7% perf-profile.self.cycles-pp.arch_exit_to_user_mode_prepare
4.56 ± 3% -1.3 3.25 ± 15% perf-profile.self.cycles-pp.entry_SYSCALL_64_safe_stack
4.30 ± 2% -1.1 3.19 ± 15% perf-profile.self.cycles-pp.entry_SYSCALL_64_after_hwframe
1.40 ± 7% +0.6 1.98 ± 12% perf-profile.self.cycles-pp.testcase
1.35 ± 2% +1.0 2.35 ± 13% perf-profile.self.cycles-pp.x64_sys_call
0.00 +1.7 1.68 ± 15% perf-profile.self.cycles-pp.prandom_u32_state
20.89 ± 9% +10.1 30.94 ± 10% perf-profile.self.cycles-pp.entry_SYSRETQ_unsafe_stack
Disclaimer:
Results have been estimated based on internal Intel analysis and are provided
for informational purposes only. Any difference in system hardware or software
design or configuration may affect actual performance.
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply
* RE: [PATCH v3 3/3] iommu/arm-smmu-v3: Allow ATS to be always on
From: Tian, Kevin @ 2026-03-31 8:40 UTC (permalink / raw)
To: Nicolin Chen, jgg@nvidia.com, will@kernel.org,
robin.murphy@arm.com, bhelgaas@google.com
Cc: joro@8bytes.org, praan@google.com, baolu.lu@linux.intel.com,
miko.lenczewski@arm.com, linux-arm-kernel@lists.infradead.org,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, Williams, Dan J,
jonathan.cameron@huawei.com, Vikram Sethi,
linux-cxl@vger.kernel.org
In-Reply-To: <0e8d1ee1557c54943dd15ff836576de4c3aa58b6.1772833963.git.nicolinc@nvidia.com>
> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Saturday, March 7, 2026 7:41 AM
>
> +
> + master->ats_always_on = true;
> +
> + ret = arm_smmu_alloc_cd_tables(master);
> + if (ret)
> + return ret;
> +
> +out_prepare:
> + pci_prepare_ats(pdev, stu);
> + return 0;
is there a problem leaving ats_always_on being true while
allocating cd tables fails?
^ permalink raw reply
* [PATCH v15 5/5] ring-buffer: Show commit numbers in buffer_meta file
From: Masami Hiramatsu (Google) @ 2026-03-31 8:36 UTC (permalink / raw)
To: Steven Rostedt, Catalin Marinas, Will Deacon
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers, linux-arm-kernel
In-Reply-To: <177494615421.71933.3679132057004156013.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
In addition to the index number, show the commit numbers of
each data page in per_cpu buffer_meta file.
This is useful for understanding the current status of the
persistent ring buffer. (Note that this file is shown
only for persistent ring buffer and its backup instance)
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
kernel/trace/ring_buffer.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index fb098b0b4505..5b40fea6b15d 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2209,6 +2209,7 @@ static int rbm_show(struct seq_file *m, void *v)
struct ring_buffer_per_cpu *cpu_buffer = m->private;
struct ring_buffer_cpu_meta *meta = cpu_buffer->ring_meta;
unsigned long val = (unsigned long)v;
+ struct buffer_data_page *dpage;
if (val == 1) {
seq_printf(m, "head_buffer: %d\n",
@@ -2221,7 +2222,9 @@ static int rbm_show(struct seq_file *m, void *v)
}
val -= 2;
- seq_printf(m, "buffer[%ld]: %d\n", val, meta->buffers[val]);
+ dpage = rb_range_buffer(cpu_buffer, val);
+ seq_printf(m, "buffer[%ld]: %d (commit: %ld)\n",
+ val, meta->buffers[val], local_read(&dpage->commit));
return 0;
}
^ permalink raw reply related
* [PATCH v15 4/5] ring-buffer: Add persistent ring buffer invalid-page inject test
From: Masami Hiramatsu (Google) @ 2026-03-31 8:36 UTC (permalink / raw)
To: Steven Rostedt, Catalin Marinas, Will Deacon
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers, linux-arm-kernel
In-Reply-To: <177494615421.71933.3679132057004156013.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Add a self-destractive test for the persistent ring buffer.
This will inject erroneous value to some sub-buffer pages (where
the index is even or multiples of 5) in the persistent ring buffer
when kernel gets panic, and check whether the number of detected
invalid pages and the total entry_bytes are the same as recorded
values after reboot.
This can ensure the kernel correctly recover partially corrupted
persistent ring buffer when boot.
The test only runs on the persistent ring buffer whose name is
"ptracingtest". And user has to fill it up with events before
kernel panics.
To run the test, enable CONFIG_RING_BUFFER_PERSISTENT_INJECT
and you have to setup the kernel cmdline;
reserve_mem=20M:2M:trace trace_instance=ptracingtest^traceoff@trace
panic=1
And run following commands after the 1st boot;
cd /sys/kernel/tracing/instances/ptracingtest
echo 1 > tracing_on
echo 1 > events/enable
sleep 3
echo c > /proc/sysrq-trigger
After panic message, the kernel will reboot and run the verification
on the persistent ring buffer, e.g.
Ring buffer meta [2] invalid buffer page detected
Ring buffer meta [2] is from previous boot! (318 pages discarded)
Ring buffer testing [2] invalid pages: PASSED (318/318)
Ring buffer testing [2] entry_bytes: PASSED (1300476/1300476)
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v15:
- Use pr_warn() for test result.
- Inject errors on the page index is multiples of 5 so that
this can reproduce contiguous empty pages.
Changes in v14:
- Rename config to CONFIG_RING_BUFFER_PERSISTENT_INJECT.
- Clear meta->nr_invalid/entry_bytes after testing.
- Add test commands in config comment.
Changes in v10:
- Add entry_bytes test.
- Do not compile test code if CONFIG_RING_BUFFER_PERSISTENT_SELFTEST=n.
Changes in v9:
- Test also reader pages.
---
include/linux/ring_buffer.h | 1 +
kernel/trace/Kconfig | 31 ++++++++++++++++++
kernel/trace/ring_buffer.c | 74 +++++++++++++++++++++++++++++++++++++++++++
kernel/trace/trace.c | 4 ++
4 files changed, 110 insertions(+)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 994f52b34344..0670742b2d60 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -238,6 +238,7 @@ int ring_buffer_subbuf_size_get(struct trace_buffer *buffer);
enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
+ RB_FL_TESTING = 1 << 1,
};
#ifdef CONFIG_RING_BUFFER
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index e130da35808f..07305ed6d745 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -1202,6 +1202,37 @@ config RING_BUFFER_VALIDATE_TIME_DELTAS
Only say Y if you understand what this does, and you
still want it enabled. Otherwise say N
+config RING_BUFFER_PERSISTENT_INJECT
+ bool "Enable persistent ring buffer error injection test"
+ depends on RING_BUFFER
+ help
+ Run a selftest on the persistent ring buffer which names
+ "ptracingtest" (and its backup) when panic_on_reboot by
+ invalidating ring buffer pages.
+ To use this, boot kernel with "ptracingtest" persistent
+ ring buffer, e.g.
+
+ reserve_mem=20M:2M:trace trace_instance=ptracingtest@trace panic=1
+
+ And after the 1st boot, run test command, like;
+
+ cd /sys/kernel/tracing/instances/ptracingtest
+ echo 1 > events/enable
+ echo 1 > tracing_on
+ sleep 3
+ echo c > /proc/sysrq-trigger
+
+ After panic message, the kernel reboots and show test results
+ on the boot log.
+
+ Note that user has to enable events on the persistent ring
+ buffer manually to fill up ring buffers before rebooting.
+ Since this invalidates the data on test target ring buffer,
+ "ptracingtest" persistent ring buffer must not be used for
+ actual tracing, but only for testing.
+
+ If unsure, say N
+
config MMIOTRACE_TEST
tristate "Test module for mmiotrace"
depends on MMIOTRACE && m
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 5ff632ca3858..fb098b0b4505 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -64,6 +64,10 @@ struct ring_buffer_cpu_meta {
unsigned long commit_buffer;
__u32 subbuf_size;
__u32 nr_subbufs;
+#ifdef CONFIG_RING_BUFFER_PERSISTENT_INJECT
+ __u32 nr_invalid;
+ __u32 entry_bytes;
+#endif
int buffers[];
};
@@ -2079,6 +2083,21 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
if (discarded)
pr_cont(" (%d pages discarded)", discarded);
pr_cont("\n");
+
+#ifdef CONFIG_RING_BUFFER_PERSISTENT_INJECT
+ if (meta->nr_invalid)
+ pr_warn("Ring buffer testing [%d] invalid pages: %s (%d/%d)\n",
+ cpu_buffer->cpu,
+ (discarded == meta->nr_invalid) ? "PASSED" : "FAILED",
+ discarded, meta->nr_invalid);
+ if (meta->entry_bytes)
+ pr_warn("Ring buffer testing [%d] entry_bytes: %s (%ld/%ld)\n",
+ cpu_buffer->cpu,
+ (entry_bytes == meta->entry_bytes) ? "PASSED" : "FAILED",
+ (long)entry_bytes, (long)meta->entry_bytes);
+ meta->nr_invalid = 0;
+ meta->entry_bytes = 0;
+#endif
return;
invalid:
@@ -2559,12 +2578,67 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
kfree(cpu_buffer);
}
+#ifdef CONFIG_RING_BUFFER_PERSISTENT_INJECT
+static void rb_test_inject_invalid_pages(struct trace_buffer *buffer)
+{
+ struct ring_buffer_per_cpu *cpu_buffer;
+ struct ring_buffer_cpu_meta *meta;
+ struct buffer_data_page *dpage;
+ u32 entry_bytes = 0;
+ unsigned long ptr;
+ int subbuf_size;
+ int invalid = 0;
+ int cpu;
+ int i;
+
+ if (!(buffer->flags & RB_FL_TESTING))
+ return;
+
+ guard(preempt)();
+ cpu = smp_processor_id();
+
+ cpu_buffer = buffer->buffers[cpu];
+ meta = cpu_buffer->ring_meta;
+ ptr = (unsigned long)rb_subbufs_from_meta(meta);
+ subbuf_size = meta->subbuf_size;
+
+ for (i = 0; i < meta->nr_subbufs; i++) {
+ int idx = meta->buffers[i];
+
+ dpage = (void *)(ptr + idx * subbuf_size);
+ /* Skip unused pages */
+ if (!local_read(&dpage->commit))
+ continue;
+
+ /*
+ * Invalidate even pages or multiples of 5. This will lead 3
+ * contiguous invalidated(empty) pages.
+ */
+ if (!(i & 0x1) || !(i % 5)) {
+ local_add(subbuf_size + 1, &dpage->commit);
+ invalid++;
+ } else {
+ /* Count total commit bytes. */
+ entry_bytes += local_read(&dpage->commit);
+ }
+ }
+
+ pr_info("Inject invalidated %d pages on CPU%d, total size: %ld\n",
+ invalid, cpu, (long)entry_bytes);
+ meta->nr_invalid = invalid;
+ meta->entry_bytes = entry_bytes;
+}
+#else /* !CONFIG_RING_BUFFER_PERSISTENT_INJECT */
+#define rb_test_inject_invalid_pages(buffer) do { } while (0)
+#endif
+
/* Stop recording on a persistent buffer and flush cache if needed. */
static int rb_flush_buffer_cb(struct notifier_block *nb, unsigned long event, void *data)
{
struct trace_buffer *buffer = container_of(nb, struct trace_buffer, flush_nb);
ring_buffer_record_off(buffer);
+ rb_test_inject_invalid_pages(buffer);
arch_ring_buffer_flush_range(buffer->range_addr_start, buffer->range_addr_end);
return NOTIFY_DONE;
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4189ec9df6a5..108b0d16badf 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9366,6 +9366,8 @@ static void setup_trace_scratch(struct trace_array *tr,
memset(tscratch, 0, size);
}
+#define TRACE_TEST_PTRACING_NAME "ptracingtest"
+
static int
allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, unsigned long size)
{
@@ -9378,6 +9380,8 @@ allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, unsigned
buf->tr = tr;
if (tr->range_addr_start && tr->range_addr_size) {
+ if (!strcmp(tr->name, TRACE_TEST_PTRACING_NAME))
+ rb_flags |= RB_FL_TESTING;
/* Add scratch buffer to handle 128 modules */
buf->buffer = ring_buffer_alloc_range(size, rb_flags, 0,
tr->range_addr_start,
^ permalink raw reply related
* Re: [PATCH v4 1/9] dt-bindings: mfd: mt6397: Add MT6392 PMIC
From: Luca Leonardo Scorcia @ 2026-03-31 8:36 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: linux-mediatek, Fabien Parent, Val Packett, Dmitry Torokhov,
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Sen Chu,
Sean Wang, Macpaul Lin, Lee Jones, Matthias Brugger,
AngeloGioacchino Del Regno, Linus Walleij, Liam Girdwood,
Mark Brown, Louis-Alexis Eyraud, Gary Bisson, Julien Massot,
Chen Zhong, linux-input, devicetree, linux-kernel, linux-pm,
linux-arm-kernel, linux-gpio
In-Reply-To: <20260331-flawless-bronze-lorikeet-59a6ff@quoll>
> > - required:
> > - - compatible
>
> Not really, this affects existing ABI and might make the child schema
> being applied. Basically regulators node can be anything now.
>
> This is definitely not a binding we want. The syntax for parent schema
> when listing only compatibles is requiring this compatible. You cannot
> have here whatever empty node.
Hi, it felt quite strange to me too, but that's what I thought you
meant with your previous suggestion [1].
To keep the required attribute I would be happy to reintroduce the
compatible here, in the regulator schema and the pmic dtsi.
Before I do that and resubmit, could you please help me understand
what you meant before?
Thank you!
[1] https://lists.infradead.org/pipermail/linux-mediatek/2026-March/105060.html
--
Luca Leonardo Scorcia
l.scorcia@gmail.com
^ permalink raw reply
* [PATCH v15 3/5] ring-buffer: Skip invalid sub-buffers when rewinding persistent ring buffer
From: Masami Hiramatsu (Google) @ 2026-03-31 8:36 UTC (permalink / raw)
To: Steven Rostedt, Catalin Marinas, Will Deacon
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers, linux-arm-kernel
In-Reply-To: <177494615421.71933.3679132057004156013.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Skip invalid sub-buffers when rewinding the persistent ring buffer
instead of stopping the rewinding the ring buffer. The skipped
buffers are cleared.
To ensure the rewinding stops at the unused page, this also clears
buffer_data_page::time_stamp when tracing resets the buffer. This
allows us to identify unused pages and empty pages.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v12:
- Fix build error.
Changes in v11:
- Reset timestamp when the buffer is invalid.
- When rewinding, skip subbuf page if timestamp is wrong and
check timestamp after validating buffer data page.
Changes in v10:
- Newly added.
---
kernel/trace/ring_buffer.c | 76 +++++++++++++++++++++++++-------------------
1 file changed, 43 insertions(+), 33 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2a6254edae5f..5ff632ca3858 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -363,6 +363,7 @@ struct buffer_page {
static void rb_init_page(struct buffer_data_page *bpage)
{
local_set(&bpage->commit, 0);
+ bpage->time_stamp = 0;
}
static __always_inline unsigned int rb_page_commit(struct buffer_page *bpage)
@@ -1878,12 +1879,14 @@ static int rb_read_data_buffer(struct buffer_data_page *dpage, int tail, int cpu
return events;
}
-static int rb_validate_buffer(struct buffer_data_page *dpage, int cpu,
+static int rb_validate_buffer(struct buffer_page *bpage, int cpu,
struct ring_buffer_cpu_meta *meta)
{
+ struct buffer_data_page *dpage = bpage->page;
unsigned long long ts;
unsigned long tail;
u64 delta;
+ int ret = -1;
/*
* When a sub-buffer is recovered from a read, the commit value may
@@ -1892,9 +1895,17 @@ static int rb_validate_buffer(struct buffer_data_page *dpage, int cpu,
* subbuf_size is considered invalid.
*/
tail = local_read(&dpage->commit) & ~RB_MISSED_MASK;
- if (tail > meta->subbuf_size)
- return -1;
- return rb_read_data_buffer(dpage, tail, cpu, &ts, &delta);
+ if (tail <= meta->subbuf_size)
+ ret = rb_read_data_buffer(dpage, tail, cpu, &ts, &delta);
+
+ if (ret < 0) {
+ local_set(&bpage->entries, 0);
+ local_set(&bpage->page->commit, 0);
+ } else {
+ local_set(&bpage->entries, ret);
+ }
+
+ return ret;
}
/* If the meta data has been validated, now validate the events */
@@ -1915,18 +1926,14 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
orig_head = head_page = cpu_buffer->head_page;
/* Do the reader page first */
- ret = rb_validate_buffer(cpu_buffer->reader_page->page, cpu_buffer->cpu, meta);
+ ret = rb_validate_buffer(cpu_buffer->reader_page, cpu_buffer->cpu, meta);
if (ret < 0) {
pr_info("Ring buffer meta [%d] invalid reader page detected\n",
cpu_buffer->cpu);
discarded++;
- /* Instead of discard whole ring buffer, discard only this sub-buffer. */
- local_set(&cpu_buffer->reader_page->entries, 0);
- local_set(&cpu_buffer->reader_page->page->commit, 0);
} else {
entries += ret;
entry_bytes += rb_page_size(cpu_buffer->reader_page);
- local_set(&cpu_buffer->reader_page->entries, ret);
}
ts = head_page->page->time_stamp;
@@ -1945,26 +1952,33 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
if (head_page == cpu_buffer->tail_page)
break;
- /* Ensure the page has older data than head. */
- if (ts < head_page->page->time_stamp)
- break;
-
- ts = head_page->page->time_stamp;
- /* Ensure the page has correct timestamp and some data. */
- if (!ts || rb_page_commit(head_page) == 0)
- break;
-
- /* Stop rewind if the page is invalid. */
- ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu, meta);
- if (ret < 0)
+ /* Rewind until unused page (no timestamp, no commit). */
+ if (!head_page->page->time_stamp && rb_page_commit(head_page) == 0)
break;
- /* Recover the number of entries and update stats. */
- local_set(&head_page->entries, ret);
- if (ret)
- local_inc(&cpu_buffer->pages_touched);
- entries += ret;
- entry_bytes += rb_page_commit(head_page);
+ /*
+ * Skip if the page is invalid, or its timestamp is newer than the
+ * previous valid page.
+ */
+ ret = rb_validate_buffer(head_page, cpu_buffer->cpu, meta);
+ if (ret >= 0 && ts < head_page->page->time_stamp) {
+ local_set(&head_page->entries, 0);
+ local_set(&head_page->page->commit, 0);
+ head_page->page->time_stamp = ts;
+ ret = -1;
+ }
+ if (ret < 0) {
+ if (!discarded)
+ pr_info("Ring buffer meta [%d] invalid buffer page detected\n",
+ cpu_buffer->cpu);
+ discarded++;
+ } else {
+ entries += ret;
+ entry_bytes += rb_page_size(head_page);
+ if (ret > 0)
+ local_inc(&cpu_buffer->pages_touched);
+ ts = head_page->page->time_stamp;
+ }
}
if (i)
pr_info("Ring buffer [%d] rewound %d pages\n", cpu_buffer->cpu, i);
@@ -2034,15 +2048,12 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
if (head_page == cpu_buffer->reader_page)
continue;
- ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu, meta);
+ ret = rb_validate_buffer(head_page, cpu_buffer->cpu, meta);
if (ret < 0) {
if (!discarded)
pr_info("Ring buffer meta [%d] invalid buffer page detected\n",
cpu_buffer->cpu);
discarded++;
- /* Instead of discard whole ring buffer, discard only this sub-buffer. */
- local_set(&head_page->entries, 0);
- local_set(&head_page->page->commit, 0);
} else {
/* If the buffer has content, update pages_touched */
if (ret)
@@ -2050,7 +2061,6 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
entries += ret;
entry_bytes += rb_page_size(head_page);
- local_set(&head_page->entries, ret);
}
if (head_page == cpu_buffer->commit_page)
break;
@@ -2083,7 +2093,7 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
/* Reset all the subbuffers */
for (i = 0; i < meta->nr_subbufs - 1; i++, rb_inc_page(&head_page)) {
local_set(&head_page->entries, 0);
- local_set(&head_page->page->commit, 0);
+ rb_init_page(head_page->page);
}
}
^ permalink raw reply related
* [PATCH v15 2/5] ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer
From: Masami Hiramatsu (Google) @ 2026-03-31 8:36 UTC (permalink / raw)
To: Steven Rostedt, Catalin Marinas, Will Deacon
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers, linux-arm-kernel
In-Reply-To: <177494615421.71933.3679132057004156013.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Skip invalid sub-buffers when validating the persistent ring buffer
instead of discarding the entire ring buffer. Only skipped buffers
are invalidated (cleared).
If the cache data in memory fails to be synchronized during a reboot,
the persistent ring buffer may become partially corrupted, but other
sub-buffers may still contain readable event data. Only discard the
subbuffers that are found to be corrupted.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v15:
- Skip reader_page loop check on persistent ring buffer because
there can be contiguous empty(invalidated) pages.
- Do not show discarded page number information if it is 0.
Changes in v11:
- Fix a typo.
Changes in v9:
- Add meta->subbuf_size check.
- Fix a typo.
- Handle invalid reader_page case.
Changes in v8:
- Add comment in rb_valudate_buffer()
- Clear the RB_MISSED_* flags in rb_valudate_buffer() instead of
skipping subbuf.
- Remove unused subbuf local variable from rb_cpu_meta_valid().
Changes in v7:
- Combined with Handling RB_MISSED_* flags patch, focus on validation at boot.
- Remove checking subbuffer data when validating metadata, because it should be done
later.
- Do not mark the discarded sub buffer page but just reset it.
Changes in v6:
- Show invalid page detection message once per CPU.
Changes in v5:
- Instead of showing errors for each page, just show the number
of discarded pages at last.
Changes in v3:
- Record missed data event on commit.
---
kernel/trace/ring_buffer.c | 109 ++++++++++++++++++++++++++------------------
1 file changed, 65 insertions(+), 44 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 3e793bd1c134..2a6254edae5f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -370,6 +370,12 @@ static __always_inline unsigned int rb_page_commit(struct buffer_page *bpage)
return local_read(&bpage->page->commit);
}
+/* Size is determined by what has been committed */
+static __always_inline unsigned int rb_page_size(struct buffer_page *bpage)
+{
+ return rb_page_commit(bpage) & ~RB_MISSED_MASK;
+}
+
static void free_buffer_page(struct buffer_page *bpage)
{
/* Range pages are not to be freed */
@@ -1762,7 +1768,6 @@ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu,
unsigned long *subbuf_mask)
{
int subbuf_size = PAGE_SIZE;
- struct buffer_data_page *subbuf;
unsigned long buffers_start;
unsigned long buffers_end;
int i;
@@ -1770,6 +1775,11 @@ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu,
if (!subbuf_mask)
return false;
+ if (meta->subbuf_size != PAGE_SIZE) {
+ pr_info("Ring buffer boot meta [%d] invalid subbuf_size\n", cpu);
+ return false;
+ }
+
buffers_start = meta->first_buffer;
buffers_end = meta->first_buffer + (subbuf_size * meta->nr_subbufs);
@@ -1786,11 +1796,12 @@ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu,
return false;
}
- subbuf = rb_subbufs_from_meta(meta);
-
bitmap_clear(subbuf_mask, 0, meta->nr_subbufs);
- /* Is the meta buffers and the subbufs themselves have correct data? */
+ /*
+ * Ensure the meta::buffers array has correct data. The data in each subbufs
+ * are checked later in rb_meta_validate_events().
+ */
for (i = 0; i < meta->nr_subbufs; i++) {
if (meta->buffers[i] < 0 ||
meta->buffers[i] >= meta->nr_subbufs) {
@@ -1798,18 +1809,12 @@ static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu,
return false;
}
- if ((unsigned)local_read(&subbuf->commit) > subbuf_size) {
- pr_info("Ring buffer boot meta [%d] buffer invalid commit\n", cpu);
- return false;
- }
-
if (test_bit(meta->buffers[i], subbuf_mask)) {
pr_info("Ring buffer boot meta [%d] array has duplicates\n", cpu);
return false;
}
set_bit(meta->buffers[i], subbuf_mask);
- subbuf = (void *)subbuf + subbuf_size;
}
return true;
@@ -1873,13 +1878,22 @@ static int rb_read_data_buffer(struct buffer_data_page *dpage, int tail, int cpu
return events;
}
-static int rb_validate_buffer(struct buffer_data_page *dpage, int cpu)
+static int rb_validate_buffer(struct buffer_data_page *dpage, int cpu,
+ struct ring_buffer_cpu_meta *meta)
{
unsigned long long ts;
+ unsigned long tail;
u64 delta;
- int tail;
- tail = local_read(&dpage->commit);
+ /*
+ * When a sub-buffer is recovered from a read, the commit value may
+ * have RB_MISSED_* bits set, as these bits are reset on reuse.
+ * Even after clearing these bits, a commit value greater than the
+ * subbuf_size is considered invalid.
+ */
+ tail = local_read(&dpage->commit) & ~RB_MISSED_MASK;
+ if (tail > meta->subbuf_size)
+ return -1;
return rb_read_data_buffer(dpage, tail, cpu, &ts, &delta);
}
@@ -1890,6 +1904,7 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
struct buffer_page *head_page, *orig_head;
unsigned long entry_bytes = 0;
unsigned long entries = 0;
+ int discarded = 0;
int ret;
u64 ts;
int i;
@@ -1900,14 +1915,19 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
orig_head = head_page = cpu_buffer->head_page;
/* Do the reader page first */
- ret = rb_validate_buffer(cpu_buffer->reader_page->page, cpu_buffer->cpu);
+ ret = rb_validate_buffer(cpu_buffer->reader_page->page, cpu_buffer->cpu, meta);
if (ret < 0) {
- pr_info("Ring buffer reader page is invalid\n");
- goto invalid;
+ pr_info("Ring buffer meta [%d] invalid reader page detected\n",
+ cpu_buffer->cpu);
+ discarded++;
+ /* Instead of discard whole ring buffer, discard only this sub-buffer. */
+ local_set(&cpu_buffer->reader_page->entries, 0);
+ local_set(&cpu_buffer->reader_page->page->commit, 0);
+ } else {
+ entries += ret;
+ entry_bytes += rb_page_size(cpu_buffer->reader_page);
+ local_set(&cpu_buffer->reader_page->entries, ret);
}
- entries += ret;
- entry_bytes += local_read(&cpu_buffer->reader_page->page->commit);
- local_set(&cpu_buffer->reader_page->entries, ret);
ts = head_page->page->time_stamp;
@@ -1935,7 +1955,7 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
break;
/* Stop rewind if the page is invalid. */
- ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu);
+ ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu, meta);
if (ret < 0)
break;
@@ -2014,21 +2034,24 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
if (head_page == cpu_buffer->reader_page)
continue;
- ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu);
+ ret = rb_validate_buffer(head_page->page, cpu_buffer->cpu, meta);
if (ret < 0) {
- pr_info("Ring buffer meta [%d] invalid buffer page\n",
- cpu_buffer->cpu);
- goto invalid;
- }
-
- /* If the buffer has content, update pages_touched */
- if (ret)
- local_inc(&cpu_buffer->pages_touched);
-
- entries += ret;
- entry_bytes += local_read(&head_page->page->commit);
- local_set(&head_page->entries, ret);
+ if (!discarded)
+ pr_info("Ring buffer meta [%d] invalid buffer page detected\n",
+ cpu_buffer->cpu);
+ discarded++;
+ /* Instead of discard whole ring buffer, discard only this sub-buffer. */
+ local_set(&head_page->entries, 0);
+ local_set(&head_page->page->commit, 0);
+ } else {
+ /* If the buffer has content, update pages_touched */
+ if (ret)
+ local_inc(&cpu_buffer->pages_touched);
+ entries += ret;
+ entry_bytes += rb_page_size(head_page);
+ local_set(&head_page->entries, ret);
+ }
if (head_page == cpu_buffer->commit_page)
break;
}
@@ -2042,7 +2065,10 @@ static void rb_meta_validate_events(struct ring_buffer_per_cpu *cpu_buffer)
local_set(&cpu_buffer->entries, entries);
local_set(&cpu_buffer->entries_bytes, entry_bytes);
- pr_info("Ring buffer meta [%d] is from previous boot!\n", cpu_buffer->cpu);
+ pr_info("Ring buffer meta [%d] is from previous boot!", cpu_buffer->cpu);
+ if (discarded)
+ pr_cont(" (%d pages discarded)", discarded);
+ pr_cont("\n");
return;
invalid:
@@ -3329,12 +3355,6 @@ rb_iter_head_event(struct ring_buffer_iter *iter)
return NULL;
}
-/* Size is determined by what has been committed */
-static __always_inline unsigned rb_page_size(struct buffer_page *bpage)
-{
- return rb_page_commit(bpage) & ~RB_MISSED_MASK;
-}
-
static __always_inline unsigned
rb_commit_index(struct ring_buffer_per_cpu *cpu_buffer)
{
@@ -5647,11 +5667,12 @@ __rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
again:
/*
* This should normally only loop twice. But because the
- * start of the reader inserts an empty page, it causes
- * a case where we will loop three times. There should be no
- * reason to loop four times (that I know of).
+ * start of the reader inserts an empty page, it causes a
+ * case where we will loop three times. There should be no
+ * reason to loop four times unless the ring buffer is a
+ * recovered persistent ring buffer.
*/
- if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) {
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3 && !cpu_buffer->ring_meta)) {
reader = NULL;
goto out;
}
^ permalink raw reply related
* [PATCH v15 1/5] ring-buffer: Flush and stop persistent ring buffer on panic
From: Masami Hiramatsu (Google) @ 2026-03-31 8:36 UTC (permalink / raw)
To: Steven Rostedt, Catalin Marinas, Will Deacon
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers, linux-arm-kernel
In-Reply-To: <177494615421.71933.3679132057004156013.stgit@mhiramat.tok.corp.google.com>
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
On real hardware, panic and machine reboot may not flush hardware cache
to memory. This means the persistent ring buffer, which relies on a
coherent state of memory, may not have its events written to the buffer
and they may be lost. Moreover, there may be inconsistency with the
counters which are used for validation of the integrity of the
persistent ring buffer which may cause all data to be discarded.
To avoid this issue, stop recording of the ring buffer on panic and
flush the cache of the ring buffer's memory.
Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
Changes in v13:
- Fix a rebase conflict.
Changes in v11:
- Do nothing by default since flush_cache_vmap() does nothing on x86
but it can cause deadlock on some architectures via on_each_cpu()
because other CPUs will be stoppped when panic notifier is called.
Changes in v9:
- Fix typo of & to &&.
- Fix typo of "Generic"
Changes in v6:
- Introduce asm/ring_buffer.h for arch_ring_buffer_flush_range().
- Use flush_cache_vmap() instead of flush_cache_all().
Changes in v5:
- Use ring_buffer_record_off() instead of ring_buffer_record_disable().
- Use flush_cache_all() to ensure flush all cache.
Changes in v3:
- update patch description.
---
arch/alpha/include/asm/Kbuild | 1 +
arch/arc/include/asm/Kbuild | 1 +
arch/arm/include/asm/Kbuild | 1 +
arch/arm64/include/asm/ring_buffer.h | 10 ++++++++++
arch/csky/include/asm/Kbuild | 1 +
arch/hexagon/include/asm/Kbuild | 1 +
arch/loongarch/include/asm/Kbuild | 1 +
arch/m68k/include/asm/Kbuild | 1 +
arch/microblaze/include/asm/Kbuild | 1 +
arch/mips/include/asm/Kbuild | 1 +
arch/nios2/include/asm/Kbuild | 1 +
arch/openrisc/include/asm/Kbuild | 1 +
arch/parisc/include/asm/Kbuild | 1 +
arch/powerpc/include/asm/Kbuild | 1 +
arch/riscv/include/asm/Kbuild | 1 +
arch/s390/include/asm/Kbuild | 1 +
arch/sh/include/asm/Kbuild | 1 +
arch/sparc/include/asm/Kbuild | 1 +
arch/um/include/asm/Kbuild | 1 +
arch/x86/include/asm/Kbuild | 1 +
arch/xtensa/include/asm/Kbuild | 1 +
include/asm-generic/ring_buffer.h | 13 +++++++++++++
kernel/trace/ring_buffer.c | 22 ++++++++++++++++++++++
23 files changed, 65 insertions(+)
create mode 100644 arch/arm64/include/asm/ring_buffer.h
create mode 100644 include/asm-generic/ring_buffer.h
diff --git a/arch/alpha/include/asm/Kbuild b/arch/alpha/include/asm/Kbuild
index 483965c5a4de..b154b4e3dfa8 100644
--- a/arch/alpha/include/asm/Kbuild
+++ b/arch/alpha/include/asm/Kbuild
@@ -5,4 +5,5 @@ generic-y += agp.h
generic-y += asm-offsets.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 4c69522e0328..483caacc6988 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -5,5 +5,6 @@ generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index 03657ff8fbe3..decad5f2c826 100644
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -3,6 +3,7 @@ generic-y += early_ioremap.h
generic-y += extable.h
generic-y += flat.h
generic-y += parport.h
+generic-y += ring_buffer.h
generated-y += mach-types.h
generated-y += unistd-nr.h
diff --git a/arch/arm64/include/asm/ring_buffer.h b/arch/arm64/include/asm/ring_buffer.h
new file mode 100644
index 000000000000..62316c406888
--- /dev/null
+++ b/arch/arm64/include/asm/ring_buffer.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_ARM64_RING_BUFFER_H
+#define _ASM_ARM64_RING_BUFFER_H
+
+#include <asm/cacheflush.h>
+
+/* Flush D-cache on persistent ring buffer */
+#define arch_ring_buffer_flush_range(start, end) dcache_clean_pop(start, end)
+
+#endif /* _ASM_ARM64_RING_BUFFER_H */
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 3a5c7f6e5aac..7dca0c6cdc84 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -9,6 +9,7 @@ generic-y += qrwlock.h
generic-y += qrwlock_types.h
generic-y += qspinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += vmlinux.lds.h
generic-y += text-patching.h
diff --git a/arch/hexagon/include/asm/Kbuild b/arch/hexagon/include/asm/Kbuild
index 1efa1e993d4b..0f887d4238ed 100644
--- a/arch/hexagon/include/asm/Kbuild
+++ b/arch/hexagon/include/asm/Kbuild
@@ -5,4 +5,5 @@ generic-y += extable.h
generic-y += iomap.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/loongarch/include/asm/Kbuild b/arch/loongarch/include/asm/Kbuild
index 9034b583a88a..7e92957baf6a 100644
--- a/arch/loongarch/include/asm/Kbuild
+++ b/arch/loongarch/include/asm/Kbuild
@@ -10,5 +10,6 @@ generic-y += qrwlock.h
generic-y += user.h
generic-y += ioctl.h
generic-y += mmzone.h
+generic-y += ring_buffer.h
generic-y += statfs.h
generic-y += text-patching.h
diff --git a/arch/m68k/include/asm/Kbuild b/arch/m68k/include/asm/Kbuild
index b282e0dd8dc1..62543bf305ff 100644
--- a/arch/m68k/include/asm/Kbuild
+++ b/arch/m68k/include/asm/Kbuild
@@ -3,5 +3,6 @@ generated-y += syscall_table.h
generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += spinlock.h
generic-y += text-patching.h
diff --git a/arch/microblaze/include/asm/Kbuild b/arch/microblaze/include/asm/Kbuild
index 7178f990e8b3..0030309b47ad 100644
--- a/arch/microblaze/include/asm/Kbuild
+++ b/arch/microblaze/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += syscalls.h
generic-y += tlb.h
generic-y += user.h
diff --git a/arch/mips/include/asm/Kbuild b/arch/mips/include/asm/Kbuild
index 684569b2ecd6..9771c3d85074 100644
--- a/arch/mips/include/asm/Kbuild
+++ b/arch/mips/include/asm/Kbuild
@@ -12,5 +12,6 @@ generic-y += mcs_spinlock.h
generic-y += parport.h
generic-y += qrwlock.h
generic-y += qspinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/arch/nios2/include/asm/Kbuild b/arch/nios2/include/asm/Kbuild
index 28004301c236..0a2530964413 100644
--- a/arch/nios2/include/asm/Kbuild
+++ b/arch/nios2/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += cmpxchg.h
generic-y += extable.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += spinlock.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild
index cef49d60d74c..8aa34621702d 100644
--- a/arch/openrisc/include/asm/Kbuild
+++ b/arch/openrisc/include/asm/Kbuild
@@ -8,4 +8,5 @@ generic-y += spinlock_types.h
generic-y += spinlock.h
generic-y += qrwlock_types.h
generic-y += qrwlock.h
+generic-y += ring_buffer.h
generic-y += user.h
diff --git a/arch/parisc/include/asm/Kbuild b/arch/parisc/include/asm/Kbuild
index 4fb596d94c89..d48d158f7241 100644
--- a/arch/parisc/include/asm/Kbuild
+++ b/arch/parisc/include/asm/Kbuild
@@ -4,4 +4,5 @@ generated-y += syscall_table_64.h
generic-y += agp.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
diff --git a/arch/powerpc/include/asm/Kbuild b/arch/powerpc/include/asm/Kbuild
index 2e23533b67e3..805b5aeebb6f 100644
--- a/arch/powerpc/include/asm/Kbuild
+++ b/arch/powerpc/include/asm/Kbuild
@@ -5,4 +5,5 @@ generated-y += syscall_table_spu.h
generic-y += agp.h
generic-y += mcs_spinlock.h
generic-y += qrwlock.h
+generic-y += ring_buffer.h
generic-y += early_ioremap.h
diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index bd5fc9403295..7721b63642f4 100644
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -14,5 +14,6 @@ generic-y += ticket_spinlock.h
generic-y += qrwlock.h
generic-y += qrwlock_types.h
generic-y += qspinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += vmlinux.lds.h
diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index 80bad7de7a04..0c1fc47c3ba0 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -7,3 +7,4 @@ generated-y += unistd_nr.h
generic-y += asm-offsets.h
generic-y += mcs_spinlock.h
generic-y += mmzone.h
+generic-y += ring_buffer.h
diff --git a/arch/sh/include/asm/Kbuild b/arch/sh/include/asm/Kbuild
index 4d3f10ed8275..f0403d3ee8ab 100644
--- a/arch/sh/include/asm/Kbuild
+++ b/arch/sh/include/asm/Kbuild
@@ -3,4 +3,5 @@ generated-y += syscall_table.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
generic-y += parport.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index 17ee8a273aa6..49c6bb326b75 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -4,4 +4,5 @@ generated-y += syscall_table_64.h
generic-y += agp.h
generic-y += kvm_para.h
generic-y += mcs_spinlock.h
+generic-y += ring_buffer.h
generic-y += text-patching.h
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 1b9b82bbe322..2a1629ba8140 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -17,6 +17,7 @@ generic-y += module.lds.h
generic-y += parport.h
generic-y += percpu.h
generic-y += preempt.h
+generic-y += ring_buffer.h
generic-y += runtime-const.h
generic-y += softirq_stack.h
generic-y += switch_to.h
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 4566000e15c4..078fd2c0d69d 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -14,3 +14,4 @@ generic-y += early_ioremap.h
generic-y += fprobe.h
generic-y += mcs_spinlock.h
generic-y += mmzone.h
+generic-y += ring_buffer.h
diff --git a/arch/xtensa/include/asm/Kbuild b/arch/xtensa/include/asm/Kbuild
index 13fe45dea296..e57af619263a 100644
--- a/arch/xtensa/include/asm/Kbuild
+++ b/arch/xtensa/include/asm/Kbuild
@@ -6,5 +6,6 @@ generic-y += mcs_spinlock.h
generic-y += parport.h
generic-y += qrwlock.h
generic-y += qspinlock.h
+generic-y += ring_buffer.h
generic-y += user.h
generic-y += text-patching.h
diff --git a/include/asm-generic/ring_buffer.h b/include/asm-generic/ring_buffer.h
new file mode 100644
index 000000000000..201d2aee1005
--- /dev/null
+++ b/include/asm-generic/ring_buffer.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Generic arch dependent ring_buffer macros.
+ */
+#ifndef __ASM_GENERIC_RING_BUFFER_H__
+#define __ASM_GENERIC_RING_BUFFER_H__
+
+#include <linux/cacheflush.h>
+
+/* Flush cache on ring buffer range if needed. Do nothing by default. */
+#define arch_ring_buffer_flush_range(start, end) do { } while (0)
+
+#endif /* __ASM_GENERIC_RING_BUFFER_H__ */
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 8b6c39bba56d..3e793bd1c134 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -7,6 +7,7 @@
#include <linux/ring_buffer_types.h>
#include <linux/sched/isolation.h>
#include <linux/trace_recursion.h>
+#include <linux/panic_notifier.h>
#include <linux/trace_events.h>
#include <linux/ring_buffer.h>
#include <linux/trace_clock.h>
@@ -31,6 +32,7 @@
#include <linux/oom.h>
#include <linux/mm.h>
+#include <asm/ring_buffer.h>
#include <asm/local64.h>
#include <asm/local.h>
#include <asm/setup.h>
@@ -559,6 +561,7 @@ struct trace_buffer {
unsigned long range_addr_start;
unsigned long range_addr_end;
+ struct notifier_block flush_nb;
struct ring_buffer_meta *meta;
@@ -2520,6 +2523,16 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
kfree(cpu_buffer);
}
+/* Stop recording on a persistent buffer and flush cache if needed. */
+static int rb_flush_buffer_cb(struct notifier_block *nb, unsigned long event, void *data)
+{
+ struct trace_buffer *buffer = container_of(nb, struct trace_buffer, flush_nb);
+
+ ring_buffer_record_off(buffer);
+ arch_ring_buffer_flush_range(buffer->range_addr_start, buffer->range_addr_end);
+ return NOTIFY_DONE;
+}
+
static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags,
int order, unsigned long start,
unsigned long end,
@@ -2650,6 +2663,12 @@ static struct trace_buffer *alloc_buffer(unsigned long size, unsigned flags,
mutex_init(&buffer->mutex);
+ /* Persistent ring buffer needs to flush cache before reboot. */
+ if (start && end) {
+ buffer->flush_nb.notifier_call = rb_flush_buffer_cb;
+ atomic_notifier_chain_register(&panic_notifier_list, &buffer->flush_nb);
+ }
+
return_ptr(buffer);
fail_free_buffers:
@@ -2748,6 +2767,9 @@ ring_buffer_free(struct trace_buffer *buffer)
{
int cpu;
+ if (buffer->range_addr_start && buffer->range_addr_end)
+ atomic_notifier_chain_unregister(&panic_notifier_list, &buffer->flush_nb);
+
cpuhp_state_remove_instance(CPUHP_TRACE_RB_PREPARE, &buffer->node);
irq_work_sync(&buffer->irq_work.work);
^ permalink raw reply related
* [PATCH v15 0/5] ring-buffer: Making persistent ring buffers robust
From: Masami Hiramatsu (Google) @ 2026-03-31 8:35 UTC (permalink / raw)
To: Steven Rostedt, Catalin Marinas, Will Deacon
Cc: Masami Hiramatsu, Mathieu Desnoyers, linux-kernel,
linux-trace-kernel, Ian Rogers, linux-arm-kernel
Hi,
Here is the 15th version of improvement patches for making persistent
ring buffers robust to failures.
The previous version is here:
https://lore.kernel.org/all/177487498530.3463592.12715592581212799257.stgit@mhiramat.tok.corp.google.com/
This version fixes warning if reader see contiguous multiple
empty (invalidated) pages on the recovered persistent ring buffer
[2/5], do not show discarded pages if it is 0 [2/5], use pr_warn()
for showing test result [4/5], and inject errors to the pages which
is multiples of 5 too[4/5].
This also drops "Reset RB_MISSED_* flags" patch, and add a patch
to show commit number on each data page [5/5] for debugging.
In this version, I added arm64 maitainers to request their
review for [1/5], which introduces asm/ring_buffer.h for flushing
the cache before reboot.
Thank you,
---
Masami Hiramatsu (Google) (5):
ring-buffer: Flush and stop persistent ring buffer on panic
ring-buffer: Skip invalid sub-buffers when validating persistent ring buffer
ring-buffer: Skip invalid sub-buffers when rewinding persistent ring buffer
ring-buffer: Add persistent ring buffer invalid-page inject test
ring-buffer: Show commit numbers in buffer_meta file
arch/alpha/include/asm/Kbuild | 1
arch/arc/include/asm/Kbuild | 1
arch/arm/include/asm/Kbuild | 1
arch/arm64/include/asm/ring_buffer.h | 10 +
arch/csky/include/asm/Kbuild | 1
arch/hexagon/include/asm/Kbuild | 1
arch/loongarch/include/asm/Kbuild | 1
arch/m68k/include/asm/Kbuild | 1
arch/microblaze/include/asm/Kbuild | 1
arch/mips/include/asm/Kbuild | 1
arch/nios2/include/asm/Kbuild | 1
arch/openrisc/include/asm/Kbuild | 1
arch/parisc/include/asm/Kbuild | 1
arch/powerpc/include/asm/Kbuild | 1
arch/riscv/include/asm/Kbuild | 1
arch/s390/include/asm/Kbuild | 1
arch/sh/include/asm/Kbuild | 1
arch/sparc/include/asm/Kbuild | 1
arch/um/include/asm/Kbuild | 1
arch/x86/include/asm/Kbuild | 1
arch/xtensa/include/asm/Kbuild | 1
include/asm-generic/ring_buffer.h | 13 ++
include/linux/ring_buffer.h | 1
kernel/trace/Kconfig | 31 ++++
kernel/trace/ring_buffer.c | 258 ++++++++++++++++++++++++++--------
kernel/trace/trace.c | 4 +
26 files changed, 273 insertions(+), 64 deletions(-)
create mode 100644 arch/arm64/include/asm/ring_buffer.h
create mode 100644 include/asm-generic/ring_buffer.h
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: [PATCH v2 1/4] dt-bindings: usb: dwc3-xilinx: Add MMI USB support on Versal Gen2 platform
From: Krzysztof Kozlowski @ 2026-03-31 8:25 UTC (permalink / raw)
To: Radhey Shyam Pandey
Cc: gregkh, robh, krzk+dt, conor+dt, michal.simek, Thinh.Nguyen,
p.zabel, linux-usb, devicetree, linux-arm-kernel, linux-kernel,
git
In-Reply-To: <20260330190304.1841593-2-radhey.shyam.pandey@amd.com>
On Tue, Mar 31, 2026 at 12:33:01AM +0530, Radhey Shyam Pandey wrote:
> Versal Gen2 platform multimedia integrated (MMI) module has a USB3.2 Gen
> 2x1 Dual Role Device IP. Introduce a new compatibility string to support
> it. The USB wrapper registers reside in the MMI UDH system-level control
> registers (SLCR) block, so instead of a dedicated reg property, add
> xlnx,usb-syscon phandle with four cells specifying register offsets for
> USB2 PHY, USB3 PHY, USB DRD, and USB power configuration within the SLCR.
>
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
> ---
> Changes for v2:
> - Add blank line after compatible as suggested by Krzysztof.
> - Retain the mmi suffix in the compatible string, as this USB 3.2 Gen2
> IP from Synopsys is part of the dedicated Multimedia Interface. The
> Versal Gen2 platform also includes a separate USB 2.0 controller,
> and the mmi suffix uniquely distinguishes between the two USB
> controllers. MMI is an independent subsystem particularly targeted for
> deployment in Multi-Media related applications. The MMI block include
> following submodules: UDH: USB3.2 Gen 2x1 Dual Role Device, DisplayPort
> Transmit Controller, Security Module (ESM) for DisplayPort and HDMI
> Controllers, DP AUX-I2C PHY.
> - For MMI USB define parent address space i.e UDH block.
> - Fix inconsistent MHz spacing to use SI convention with spaces.
> - Move description before $ref and items in xlnx,usb-syscon property.
> - Restore original zynqmp-dwc3 example, add new versal2-mmi-dwc3 example.
> - Use 'usb' node name (without unit address) for versal2 example since
> it has no reg property.
> - Use 1/1 address/size configuration in versal2 example, use lowercase
> hex in syscon offsets.
> ---
> .../devicetree/bindings/usb/dwc3-xilinx.yaml | 70 ++++++++++++++++++-
> 1 file changed, 67 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml b/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> index d6823ef5f9a7..5e31b961aff7 100644
> --- a/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> +++ b/Documentation/devicetree/bindings/usb/dwc3-xilinx.yaml
> @@ -15,6 +15,8 @@ properties:
> - enum:
> - xlnx,zynqmp-dwc3
> - xlnx,versal-dwc3
> + - xlnx,versal2-mmi-dwc3
I am not going to ask the same questions.
Best regards,
Krzysztof
^ permalink raw reply
* Re: [GIT PULL 1/7] dt-bindings: Changes for v7.1-rc1
From: Thierry Reding @ 2026-03-31 8:25 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: arm, soc, Thierry Reding, Jon Hunter, linux-tegra,
linux-arm-kernel
In-Reply-To: <406ca5ed-4a3e-48ba-94ad-d88c53b09299@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 4247 bytes --]
On Mon, Mar 30, 2026 at 01:39:49PM +0200, Krzysztof Kozlowski wrote:
> On 29/03/2026 17:10, Thierry Reding wrote:
> > From: Thierry Reding <thierry.reding@gmail.com>
> >
> > Hi ARM SoC maintainers,
> >
> > The following changes since commit 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f:
> >
> > Linux 7.0-rc1 (2026-02-22 13:18:59 -0800)
> >
> > are available in the Git repository at:
> >
> > git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux.git tags/tegra-for-7.1-dt-bindings
> >
> > for you to fetch changes up to bed2f5b4de6c6fd8f8928f6373ad92e8795c370f:
> >
> > dt-bindings: arm: tegra: Document Jetson AGX Thor DevKit (2026-03-28 01:05:24 +0100)
> >
> > Thanks,
> > Thierry
> >
> > ----------------------------------------------------------------
> > dt-bindings: Changes for v7.1-rc1
> >
> > This contains a few conversions to DT schema along with various
> > additions and fixes to reduce the amount of validation warnings.
> >
> > Included are also a new binding for the PCIe controller found on
> > Tegra264 as well as compatible strings for the Jetson AGX Thor
> > Developer Kit.
> >
> > ----------------------------------------------------------------
> > Sumit Gupta (1):
> > dt-bindings: arm: tegra: Add Tegra238 CBB compatible strings
> >
> > Svyatoslav Ryhel (1):
> > dt-bindings: display: tegra: Document Tegra20 HDMI port
> >
> > Thierry Reding (9):
> > dt-bindings: pci: Document the NVIDIA Tegra264 PCIe controller
>
> Why are you taking subsystem patches? This was posted on 26th of March
> and was not acked by PCI maintainers.
>
> How the bindings should go is already documented, so there is no
> question here.
We've discussed this in the past and I still think your rule about DT
bindings needing to go in through the driver tree is impractical. Yes,
it means you get around the checkpatch warning about undocumented
compatible strings, but at the expense of a new warning in the Tegra
tree because the bindings aren't there.
> The question was whether you can take them if subsystem maintainer is
> non-responsive and yes, you can. You gave PCI maintainers one day before
> applying it.
I did not get a response to my suggestion about creating a shared
branch, which was included in v1 already. So I went ahead and did what
I thought was best. PCI maintainers are free to not pull this if they
don't want to. I also offered to address any further review comments if
there were any.
> > dt-bindings: phy: tegra-xusb: Document Type C support
>
> No acks, but that is waiting for one month so it is fine.
It's got a Reviewed-by from Rob and there were no corresponding driver
changes associated with it. There's literally no reason for this to go
in through a subsystem tree.
> > dt-bindings: clock: tegra124-dfll: Convert to json-schema
> > dt-bindings: interrupt-controller: tegra: Fix reg entries
> > dt-bindings: arm: tegra: Add missing compatible strings
> > dt-bindings: phy: tegra: Document Tegra210 USB PHY
> > dt-bindings: memory: Add Tegra210 memory controller bindings
> > dt-bindings: memory: tegra210: Mark EMC as cooling device
>
> That's even my subsystem and I did not ack it. You did not even sent it
> to me as requested by MAINTAINERS file (+dt is ignore alias), so
> obviously I did not even had a chance to ack it.
Ugh... really? I was Cc'ed to you as a DT maintainer as well as the
devicetree mailing list, so I'm sure you've seen it. This had also been
reviewed by Rob a long time ago, and honestly, it's also quite trivial.
It's been on the list for a month and there were no objections, so it
does pass all of the criteria you mentioned before.
> And we even had few days ago talk were I explained you how these
> bindings must go. Seeing pull request completely ignoring that
> discussion is just huge surprise.
>
> No, it cannot go in. Send patches to proper maintainers first.
Stop making these baseless accusations, Krzysztof. You were on Cc and
DT maintainers have seen and reviewed these patches. You're grasping at
straws to somehow try to make my life miserable and I don't know why.
Thierry
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^ permalink raw reply
* RE: [PATCH v3 2/3] PCI: Allow ATS to be always on for pre-CXL devices
From: Tian, Kevin @ 2026-03-31 8:24 UTC (permalink / raw)
To: Nicolin Chen, jgg@nvidia.com, will@kernel.org,
robin.murphy@arm.com, bhelgaas@google.com
Cc: joro@8bytes.org, praan@google.com, baolu.lu@linux.intel.com,
miko.lenczewski@arm.com, linux-arm-kernel@lists.infradead.org,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, Williams, Dan J,
jonathan.cameron@huawei.com, Vikram Sethi,
linux-cxl@vger.kernel.org
In-Reply-To: <c715b10b49d50eea5429454108d4221c1a78efaf.1772833963.git.nicolinc@nvidia.com>
> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Saturday, March 7, 2026 7:41 AM
>
> Some NVIDIA GPU/NIC devices, although don't implement the CXL config
> space,
> they have many CXL-like properties. Call this kind "pre-CXL".
>
> Similar to CXL.cache capaiblity, these pre-CXL devices also require the ATS
s/capaiblity/capability/
> function even when their RIDs are IOMMU bypassed, i.e. keep ATS "always
> on"
> v.s. "on demand" when a non-zero PASID line gets enabled in SVA use cases.
>
> Introduce pci_dev_specific_ats_always_on() quirk function to scan a list of
> IDs for these device. Then, include it pci_ats_always_on().
"include it *in* pci_ats_always_on()"
> +
> +/* Some pre-CXL devices require ATS on the RID when it is IOMMU-
> bypassed */
> +bool pci_dev_specific_ats_always_on(struct pci_dev *pdev)
clearer to remove "on the RID ...".
"always on" implies no condition required. and adding IOMMU bypass
info there is confusing.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
^ permalink raw reply
* [PATCH v2 3/3] crypto: atmel-sha204a - fix non-blocking read logic
From: Lothar Rubusch @ 2026-03-31 8:21 UTC (permalink / raw)
To: herbert, davem, nicolas.ferre, alexandre.belloni, claudiu.beznea,
ardb, linusw
Cc: linux-crypto, linux-arm-kernel, linux-kernel, l.rubusch
In-Reply-To: <20260331082105.697468-1-l.rubusch@gmail.com>
The non-blocking path was (also) failing to provide valid entropy
due to improper buffer management and a lack of hardware execution
time.
Ensure cmd.msecs (30ms) and cmd.rxsize (35ms) are initialized before
enqueuing the background work. Fix the data offset to skip the
1-byte hardware count header when copying bits to the caller. Correctly
return 0 (busy) to the hwrng core while hardware execution is in
progress, preventing zero-filled buffers, which was the situation
before.
With this fix applied, tests will look similar to this:
$ socat -u OPEN:/dev/hwrng,nonblock - | head -c 32 | hexdump -C
00000000 23 cc 42 3c 90 b1 38 fc 54 37 35 4b 09 c5 e1 0d |#.B<..8.T75K....|
2026/03/23 14:30:18 socat[858] E read(5, 0x55be363000, 8192): Resource temporarily unavailable
00000010 73 3b af d9 02 70 76 bd 2d 59 4b 12 01 ac ae 2b |s;...pv.-YK....+|
00000020
Fixes: da001fb651b0 ("crypto: atmel-i2c - add support for SHA204A random number generator")
Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
drivers/crypto/atmel-sha204a.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c
index 350ba8618c69..c0a1d34bbd9e 100644
--- a/drivers/crypto/atmel-sha204a.c
+++ b/drivers/crypto/atmel-sha204a.c
@@ -32,7 +32,6 @@ static void atmel_sha204a_rng_done(struct atmel_i2c_work_data *work_data,
"i2c transaction failed (%d)\n",
status);
kfree(work_data);
- rng->priv = 0;
atomic_dec(&i2c_priv->tfm_count);
return;
}
@@ -49,20 +48,19 @@ static int atmel_sha204a_rng_read_nonblocking(struct hwrng *rng, void *data,
i2c_priv = container_of(rng, struct atmel_i2c_client_priv, hwrng);
- /* Verify if data available from last run */
if (rng->priv) {
work_data = (struct atmel_i2c_work_data *)rng->priv;
- max = min(sizeof(work_data->cmd.data), max);
- memcpy(data, &work_data->cmd.data, max);
+ max = min_t(size_t, ATMEL_RNG_BLOCK_SIZE, max);
+ memcpy(data, &work_data->cmd.data[1], max);
- /* Now, free memory */
+ /* Free memory and clear the in-flight flag */
kfree(work_data);
rng->priv = 0;
atomic_dec(&i2c_priv->tfm_count);
return max;
}
- /* When a request is still in-flight but not processed */
+ /* If a request is still in-flight, return 0 (busy) */
if (atomic_read(&i2c_priv->tfm_count) > 0)
return 0;
@@ -76,8 +74,14 @@ static int atmel_sha204a_rng_read_nonblocking(struct hwrng *rng, void *data,
work_data->client = i2c_priv->client;
atmel_i2c_init_random_cmd(&work_data->cmd);
+
+ /* Set the execution time for the RNG command (from datasheet) */
+ work_data->cmd.msecs = ATMEL_RNG_EXEC_TIME;
+ work_data->cmd.rxsize = RANDOM_RSP_SIZE;
+
atmel_i2c_enqueue(work_data, atmel_sha204a_rng_done, rng);
+ /* Return 0 to indicate 'busy', data will be ready on next call */
return 0;
}
--
2.39.5
^ permalink raw reply related
* [PATCH v2 2/3] crypto: atmel-sha204a - fix truncated 32-byte blocking read
From: Lothar Rubusch @ 2026-03-31 8:21 UTC (permalink / raw)
To: herbert, davem, nicolas.ferre, alexandre.belloni, claudiu.beznea,
ardb, linusw
Cc: linux-crypto, linux-arm-kernel, linux-kernel, l.rubusch
In-Reply-To: <20260331082105.697468-1-l.rubusch@gmail.com>
The ATSHA204A returns a 35-byte packet consisting of a 1-byte count,
32 bytes of entropy, and a 2-byte CRC. The current blocking read
implementation was incorrectly copying data starting from the
count byte, leading to offset data and truncated entropy.
Additionally, the chip requires significant execution time to
generate random numbers, going by the datasheet. Reading the I2C bus
too early results in the chip NACK-ing or returning a partial buffer
followed by zeros.
Verification:
Tests before showed repeadetly reading only 8 bytes of entropy:
$ head -c 32 /dev/hwrng | hexdump -C
00000000 02 28 85 b3 47 40 f2 ee 00 00 00 00 00 00 00 00 |.(..G@..........|
00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
00000020
After this patch applied, the result will be as follows:
$ head -c 32 /dev/hwrng | hexdump -C
00000000 5a fc 3f 13 14 68 fe 06 68 0a bd 04 83 6e 09 69 |Z.?..h..h....n.i|
00000010 75 ff cf 87 10 84 3b c9 c1 df ae eb 45 53 4c c3 |u.....;.....ESL.|
00000020
Fix these issues by:
Increase cmd.msecs to 30ms to provide sufficient execution time. Then
set cmd.rxsize to RANDOM_RSP_SIZE (35 bytes) to capture the entire
hardware response. Eventually, correct the memcpy() offset to index 1 of
the data buffer to skip the count byte and retrieve exactly 32 bytes of
entropy.
Fixes: da001fb651b0 ("crypto: atmel-i2c - add support for SHA204A random number generator")
Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
drivers/crypto/atmel-sha204a.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c
index 1baf4750d311..350ba8618c69 100644
--- a/drivers/crypto/atmel-sha204a.c
+++ b/drivers/crypto/atmel-sha204a.c
@@ -18,6 +18,9 @@
#include <linux/workqueue.h>
#include "atmel-i2c.h"
+#define ATMEL_RNG_BLOCK_SIZE 32
+#define ATMEL_RNG_EXEC_TIME 30
+
static void atmel_sha204a_rng_done(struct atmel_i2c_work_data *work_data,
void *areq, int status)
{
@@ -91,13 +94,15 @@ static int atmel_sha204a_rng_read(struct hwrng *rng, void *data, size_t max,
i2c_priv = container_of(rng, struct atmel_i2c_client_priv, hwrng);
atmel_i2c_init_random_cmd(&cmd);
+ cmd.msecs = ATMEL_RNG_EXEC_TIME;
+ cmd.rxsize = RANDOM_RSP_SIZE;
ret = atmel_i2c_send_receive(i2c_priv->client, &cmd);
if (ret)
return ret;
- max = min(sizeof(cmd.data), max);
- memcpy(data, cmd.data, max);
+ max = min_t(size_t, ATMEL_RNG_BLOCK_SIZE, max);
+ memcpy(data, &cmd.data[1], max);
return max;
}
--
2.39.5
^ permalink raw reply related
* [PATCH v2 1/3] crypto: atmel-sha204a - fix memory leak at non-blocking RNG work_data
From: Lothar Rubusch @ 2026-03-31 8:21 UTC (permalink / raw)
To: herbert, davem, nicolas.ferre, alexandre.belloni, claudiu.beznea,
ardb, linusw
Cc: linux-crypto, linux-arm-kernel, linux-kernel, l.rubusch
In-Reply-To: <20260331082105.697468-1-l.rubusch@gmail.com>
The driver allocated memory for work_data in the non-blocking read
path but never free'd it again. After first read-out the memory pointer
seemed to be recycled and never was allocated again, due to some errors
in the logic, so that the leak was not growing.
Add kfree(work_data) in the completion callback on error. then add
kfree(work_data) after the data is consumed in the subsequent read
call. Finally ensure atomic_dec() is called only after the data has
been consumed or an error occurred to prevent race conditions.
Fixes: da001fb651b0 ("crypto: atmel-i2c - add support for SHA204A random number generator")
Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
drivers/crypto/atmel-sha204a.c | 44 +++++++++++++++++++++-------------
1 file changed, 27 insertions(+), 17 deletions(-)
diff --git a/drivers/crypto/atmel-sha204a.c b/drivers/crypto/atmel-sha204a.c
index 98d1023007e3..1baf4750d311 100644
--- a/drivers/crypto/atmel-sha204a.c
+++ b/drivers/crypto/atmel-sha204a.c
@@ -24,15 +24,20 @@ static void atmel_sha204a_rng_done(struct atmel_i2c_work_data *work_data,
struct atmel_i2c_client_priv *i2c_priv = work_data->ctx;
struct hwrng *rng = areq;
- if (status)
+ if (status) {
dev_warn_ratelimited(&i2c_priv->client->dev,
"i2c transaction failed (%d)\n",
status);
+ kfree(work_data);
+ rng->priv = 0;
+ atomic_dec(&i2c_priv->tfm_count);
+ return;
+ }
rng->priv = (unsigned long)work_data;
- atomic_dec(&i2c_priv->tfm_count);
}
+
static int atmel_sha204a_rng_read_nonblocking(struct hwrng *rng, void *data,
size_t max)
{
@@ -41,31 +46,36 @@ static int atmel_sha204a_rng_read_nonblocking(struct hwrng *rng, void *data,
i2c_priv = container_of(rng, struct atmel_i2c_client_priv, hwrng);
- /* keep maximum 1 asynchronous read in flight at any time */
- if (!atomic_add_unless(&i2c_priv->tfm_count, 1, 1))
- return 0;
-
+ /* Verify if data available from last run */
if (rng->priv) {
work_data = (struct atmel_i2c_work_data *)rng->priv;
max = min(sizeof(work_data->cmd.data), max);
memcpy(data, &work_data->cmd.data, max);
- rng->priv = 0;
- } else {
- work_data = kmalloc_obj(*work_data, GFP_ATOMIC);
- if (!work_data) {
- atomic_dec(&i2c_priv->tfm_count);
- return -ENOMEM;
- }
- work_data->ctx = i2c_priv;
- work_data->client = i2c_priv->client;
- max = 0;
+ /* Now, free memory */
+ kfree(work_data);
+ rng->priv = 0;
+ atomic_dec(&i2c_priv->tfm_count);
+ return max;
}
+ /* When a request is still in-flight but not processed */
+ if (atomic_read(&i2c_priv->tfm_count) > 0)
+ return 0;
+
+ /* Start a new request */
+ work_data = kmalloc_obj(*work_data, GFP_ATOMIC);
+ if (!work_data)
+ return -ENOMEM;
+
+ atomic_inc(&i2c_priv->tfm_count);
+ work_data->ctx = i2c_priv;
+ work_data->client = i2c_priv->client;
+
atmel_i2c_init_random_cmd(&work_data->cmd);
atmel_i2c_enqueue(work_data, atmel_sha204a_rng_done, rng);
- return max;
+ return 0;
}
static int atmel_sha204a_rng_read(struct hwrng *rng, void *data, size_t max,
--
2.39.5
^ permalink raw reply related
* [PATCH v2 0/3] crypto: atmel-sha204a - multiple RNG fixes
From: Lothar Rubusch @ 2026-03-31 8:21 UTC (permalink / raw)
To: herbert, davem, nicolas.ferre, alexandre.belloni, claudiu.beznea,
ardb, linusw
Cc: linux-crypto, linux-arm-kernel, linux-kernel, l.rubusch
When testing the RNG functionality on the Atmel SHA204a hardware, I
found the following issues: rngtest reported failures and hexdump
reveiled only the first 8 bytes out of 32 provided actually entropy.
Having a closer look into it, I found a (small) memory leak, missing
to free work_data, miss-reading of the count field into the entropy
fields and parts of the 32 random bytes staying 0 due to reading the
slow i2c device.
The series proposes fixes and how fixed functionality can be/was
verified. Executing rngtest afterward showed a decent result, due
to the i2c bus a bit slow.
All setups require selecting the Atmel-sha204a as active RNG.
$ cat /sys/class/misc/hw_random/rng_available
3f104000.rng 1-0064 none
$ echo 1-0064 > /sys/class/misc/hw_random/rng_current
$ cat /sys/class/misc/hw_random/rng_current
1-0064
Testing RNG properties currently shows problematic results:
$ rngtest < /dev/hwrng
rngtest 2.6
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
rngtest: starting FIPS tests...
rngtest: bits received from input: 1040032
rngtest: FIPS 140-2 successes: 0
rngtest: FIPS 140-2 failures: 52
rngtest: FIPS 140-2(2001-10-10) Monobit: 52
rngtest: FIPS 140-2(2001-10-10) Poker: 52
rngtest: FIPS 140-2(2001-10-10) Runs: 52
rngtest: FIPS 140-2(2001-10-10) Long run: 52
rngtest: FIPS 140-2(2001-10-10) Continuous run: 52
rngtest: input channel speed: (min=7.631; avg=7.804; max=7.827)Kibits/s
rngtest: FIPS tests speed: (min=32.273; avg=32.701; max=33.056)Mibits/s
rngtest: Program run time: 130177956 microseconds
Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
v1 -> v2: Removal of C++ style comment (I saw it too late, sry for that)
---
Lothar Rubusch (3):
crypto: atmel-sha204a - fix memory leak at non-blocking RNG work_data
crypto: atmel-sha204a - fix truncated 32-byte blocking read
crypto: atmel-sha204a - fix non-blocking read logic
drivers/crypto/atmel-sha204a.c | 61 ++++++++++++++++++++++------------
1 file changed, 40 insertions(+), 21 deletions(-)
base-commit: 5c52607c43c397b79a9852ce33fc61de58c3645c
--
2.39.5
^ permalink raw reply
* Re: [PATCH 5/5] lib/crc: arm: Enable arm64's NEON intrinsics implementation of crc64
From: Ard Biesheuvel @ 2026-03-31 8:20 UTC (permalink / raw)
To: Christoph Hellwig
Cc: linux-crypto, linux-arm-kernel, Demian Shulhan, Eric Biggers
In-Reply-To: <actuDkpYbzLj0sI8@infradead.org>
On Tue, 31 Mar 2026, at 08:47, Christoph Hellwig wrote:
>> depends on CRC64 && CRC_OPTIMIZATIONS
>> + default y if ARM && KERNEL_MODE_NEON && !(CPU_BIG_ENDIAN && CC_IS_CLANG)
>
> It would be useful to throw in a comment here why it is disabled for
> big-endian on clang.
>
Ack.
>> +#define crc64_be_arch crc64_be_generic
>> +
>> +static inline u64 crc64_nvme_arch(u64 crc, const u8 *p, size_t len)
>> +{
>> + if (len >= 128 && static_branch_likely(&have_pmull) &&
>> + likely(may_use_simd())) {
>> + do {
>> + size_t chunk = min_t(size_t, len & ~15, SZ_4K);
>> +
>> + scoped_ksimd()
>> + crc = crc64_nvme_arm64_c(crc, p, chunk);
>> +
>> + p += chunk;
>> + len -= chunk;
>> + } while (len >= 128);
>> + }
>
> From reading the earlier patches, I'll assume arm SIMD code is
> non-preemptable and thus you want the chunking here? Maybe add
> a little comment explaining that?
Indeed.
^ permalink raw reply
* RE: [PATCH v3 1/3] PCI: Allow ATS to be always on for CXL.cache capable devices
From: Tian, Kevin @ 2026-03-31 8:19 UTC (permalink / raw)
To: Nicolin Chen, jgg@nvidia.com, will@kernel.org,
robin.murphy@arm.com, bhelgaas@google.com
Cc: joro@8bytes.org, praan@google.com, baolu.lu@linux.intel.com,
miko.lenczewski@arm.com, linux-arm-kernel@lists.infradead.org,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, Williams, Dan J,
jonathan.cameron@huawei.com, Vikram Sethi,
linux-cxl@vger.kernel.org
In-Reply-To: <a0dd3e4cc5260f55bbec5b3ed6791def33028735.1772833963.git.nicolinc@nvidia.com>
> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Saturday, March 7, 2026 7:41 AM
>
> Controlled by the IOMMU driver, ATS is usually enabled "on demand" when
> a
> device requests a translation service from its associated IOMMU HW running
> on the channel of a given PASID. This is working even when a device has no
> translation on its RID (i.e., the RID is IOMMU bypassed).
ATS is usually enabled "on demand" when a given PASID on the device
is attached to an I/O page table. Above sounds like there will be a software
action to enable ATS upon a device translation request.
>
> However, certain PCIe devices require non-PASID ATS on their RID even
> when
> the RID is IOMMU bypassed. Call this "always on".
>
> For instance, the CXL spec notes in "3.2.5.13 Memory Type on CXL.cache":
> "To source requests on CXL.cache, devices need to get the Host Physical
> Address (HPA) from the Host by means of an ATS request on CXL.io."
>
> In other words, the CXL.cache capability requires ATS; otherwise, it can't
> access host physical memory.
>
> Introduce a new pci_ats_always_on() helper for the IOMMU driver to scan a
> PCI device and shift ATS policies between "on demand" and "always on".
>
> Add the support for CXL.cache devices first. Pre-CXL devices will be added
> in quirks.c file.
>
> Note that pci_ats_always_on() validates against pci_ats_supported(), so we
> ensure that untrusted devices (e.g. external ports) will not be always on.
> This maintains the existing ATS security policy regarding potential side-
> channel attacks via ATS.
>
> Cc: linux-cxl@vger.kernel.org
> Suggested-by: Vikram Sethi <vsethi@nvidia.com>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
with a nit:
> +/*
> + * CXL r4.0, sec 3.2.5.13 Memory Type on CXL.cache notes: to source
> requests on
> + * CXL.cache, devices need to get the Host Physical Address (HPA) from the
> Host
> + * by means of an ATS request on CXL.io.
> + *
> + * In other world, CXL.cache devices cannot access host physical memory
> without
> + * ATS.
> + */
s/world/words/
^ permalink raw reply
* Re: [GIT PULL 6/7] arm64: tegra: Device tree changes for v7.1-rc1
From: Thierry Reding @ 2026-03-31 8:13 UTC (permalink / raw)
To: Krzysztof Kozlowski
Cc: arm, soc, Thierry Reding, Jon Hunter, linux-tegra,
linux-arm-kernel
In-Reply-To: <63b6c9da-4c0e-497c-a2a6-8aa5e74e2adb@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 1228 bytes --]
On Tue, Mar 31, 2026 at 09:59:07AM +0200, Krzysztof Kozlowski wrote:
> On 29/03/2026 17:10, Thierry Reding wrote:
> > From: Thierry Reding <thierry.reding@gmail.com>
> >
> > Hi ARM SoC maintainers,
> >
> > The following changes since commit 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f:
> >
> > Linux 7.0-rc1 (2026-02-22 13:18:59 -0800)
> >
>
> I guess related to my question why patches were applied one day after
> the list:
>
> Days in linux-next:
> ----------------------------------------
> 0 | ++++++++ (8)
>
> Commits with 0 days in linux-next (8 of 8: 100.0%):
> ...
>
> So you exposed soc tree to all sort of integration issues. No, please
> keep them for some days in the next before you send them to soc, to
> allow people to test and eventually complain/report issues.
Most issues would've been caught by daily bots already. A lot of these
probably were in linux-next but changed SHAs because I rebased them on
top of the PCI bindings patch to keep the shared branch as small as
possible.
I also do fairly extensive build testing on my side before sending those
pull requests, so I don't think I've exposed the SoC tree to an unfair
amount of integration issues.
Thierry
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^ permalink raw reply
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